GB2382559A

GB2382559A - Postal processing system

Info

Publication number: GB2382559A
Application number: GB0127681A
Authority: GB
Inventors: Peter John Alistair Catherwood
Original assignee: Consignia PLC
Current assignee: Royal Mail Group Ltd
Priority date: 2001-11-19
Filing date: 2001-11-19
Publication date: 2003-06-04
Also published as: WO2003043750A1; AU2002339187A1; WO2003043750A8; GB0127681D0

Abstract

A postal processing system comprises a transport system with a guide and a plurality of carriages mounted to the guide. Each postal item being mounted to a carriage. Also disclosed is a system as already described, further comprising one or more switching points between plural transport paths. Also disclosed is a system as already described, further comprising detents retaining carriages on the guide and identification data, indicia such as barcodes. Further disclosed is a method of postal item arranging, comprising carrying postal items transversely to their plane along a constrained guide path. Further disclosed is a postal item sorting and sequencing mechanism utilising uniquely identifiable clips and connective structure directly between postal items and rails.

Description

ARRANGER OF ITEMS This invention relates to the arranging (e. g. sorting and sequencing) of postal (or similar) items.

In the case of postal items, it is desirable to arrange objects into geographical groups for convenient transportation or into the order of delivery to their addressees-thereby simplifying the task of the delivery staff, and reducing the possibility of errors or other inefficiencies. The problem is that this task, in its entirety, is non-trivial and subject to considerable commercial pressure. Objects of different sizes have to be handled and sorted and presented to the delivery staff in a manageable form.

The majority of letter handling equipment carries letters and other postal items which are gripped between pairs of belts travelling up to 4 meters per second, spaced apart along the belts at a pitch of around 400mm. Such equipment may be capable of sorting up to 35 thousand items an hour. Since it is high speed machinery, it is relatively complex, expensive, and power consuming.

An existing postal processing apparatus typically receives postal items from a number of different input streams (from direct mailers, parcel collection and letter collection. for example) and then separates the postal items (using a mechanical sorter, for instance) into letters, flat items, parcels and so on. Each then follows a path through sorting machinery which sorts the streams into geographical groups or batches (corresponding, for example,

to a local delivery round area), and then sequencing apparatus, which arranges the items for each area into a sequence corresponding to a postal deliver route taken by a postman.

The present invention therefore aims to provide improved arranging apparatus and methods for items (such as postal items) capable of sorting and/or sequencing such items. In another aspect, the present invention provides methods and apparatus for transporting such items.

In general terms, in one aspect, the present invention solves one or more of these problems by transporting and/or arranging items transverse to their plane. In this way, items can be spaced much more closely together; for example, a pitch between items of less than 10mm and preferably less than 5mm is possible. This enables the linear speed at which items are carried to be kept much slower, whilst maintaining the same through put of items per second.

In another aspect, the invention consists in mounting the items to carriages which co-operate with tracks or rails, to permit the items to be carried in constrained fashion along the tracks. Preferably, the items are suspended from the carriages below the tracks. This allow gravity to assist the movement of the items; it may permit the items to be wholly moved by gravity for part or all of their motion.

To perform arranging, switching nodes are provided. At each node, an item can be routed between two or more output paths (or from two or more input paths). In the above embodiments, the routing node can be made bi-

directional by providing a tiltable structures, so as to control the direction of routing under the influence of gravity by controlling the direction in which the structure is tilted.

Preferably, each item has an associated identifier which can be read at stages of the processing. The identifier may be attached to the carriage, or to some supporting structure of the item, rather than to the item itself.

The carriage may comprise a detachable and reusable clip, which may be secured to the item by adhesive tape. The portion of the tape attached to the item may be peelably releasable, to avoid damage to postal items such as postcards.

Further provided is a transport device for transporting a number of items, comprising a section of track, and a memory device for storing an identifier for the transport device, and/or identifiers of the items which are carried by the device.

Also provided are a carriage structure (preferably a clip) and a adhesive tape therefore, for use with the above described aspects of the invention.

According to one embodiment of the present invention there is provided postal item sorting and sequencing mechanisms utilising uniquely identifiable clips and connective structures directly between postal items and rails, devices for handling these objects on rods and rails whilst retaining their physical position relative to adjacent items, and support for association with information related to postal items both individually or as groups.

Postal items would be fitted to clips at an early stage in their journey from sender to addressee. The items may be subject to conventional processing activities associated with for example coding addressee information, cancelling stamps, revenue protection activities and service classification. The items would be sorted to intermediate destinations whilst still connected to rails. The items would then be sequenced in the correct order for final delivery whilst still connected to rails. Having been sequenced for delivery the items may be removed from the rails. These items could be maintained in this sequence up to the eventual moment of their delivery within for example a pouch, trolley or vehicle.

Further aspect and embodiments of the invention are as described and claimed herein with advantages which will be apparent from the following.

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which :- Figure 1 shows in perspective a letter attached to a clip in the embodiment; Figure 2 shows in perspective an open clip; Figure 3 shows a rod for receiving, storing, tracking and transporting objects; Figure 4 shows a section through a rod with an optional braking/locking strip; Figure 5 shows a display-end view of the rod showing its features in detail;

Figure 6 shows in perspective a partially open delivery pouch comprising a bandolier and cover, and containing postal items; Figure 7 shows a diverter for controlling lateral movements of clips; Figure 8 shows a sorting node based on the actuation of a flexible track; Figure 9 shows in perspective a possible layout of a sorting machine; Figure 10 shows in perspective a possible layout of a sequencing machine; Figure I I a is a schematic diagram showing the flow of postal items through sorting points from above; and Figure 11 b is a corresponding schematic side view; Figure 12 shows a first alternative clip and track cross section to that of Figures 2 and 4; and Figure 13 shows a second alternative cross section; Figure 14 is a schematic plan view of a sorting node of Figure 11 ; Figure 15a is a side view of the Figure 14 ; and Figure 15b is a corresponding plan view; Figure 16 shows a rotational diverter in an alternative embodiment to that of Figure 7, and Figure 17 is a flow diagram of the process performed by the embodiments.

First Embodiment A first embodiment of the invention consists of a post handling system comprising one or processing machines, which sort post into output batches, followed by one or sequencing machines, which sort the batches into a sequence. Before, after and between stages of processing and sequencing, there are provided transport routes.

The processing machines and sequencing machines, together with the transport, all comprise rails or tracks, conveniently provided overhead, making use of gravity to assist the transport of items. The items themselves are suspended from clips. The items are initially attached to clips in a first stage of processing, and the clips are attached to the rails or tracks.

The destination of the items is initially read, and associated, in a central control unit (such as the control computer controlling the sorting station) with the identification code carried on the clip supporting that item.

The sorting process for that item, and subsequent sequencing of that item, is performed in dependence upon its identification code and hence upon its destination (postal delivery address).

Structure of Clips Referring to the drawings the postal item 1 is suspended from a clip 6.

There is merit in the clips being small and narrow, for example less than 4mm deep (along their travel direction) and less than 15mm wide (transverse to their travel direction). The clips incorporate a unique coding system, for

example an embedded non-volatile electronic memory device or a bar-coded label 7 fitted in a shallow recess on one or more surfaces of the clip.

The clips are arranged to be secured to rails (not shown in Figure 1) with a compatible cross-section.

The clips may be composed of a material that has a naturally low coefficient of friction, for example nylon or, and/or may feature frictionreducing inserts 8 at their normal points of contact with the rail. The clips may incorporate small bearings or rollers (not shown) at any of their significant points of contact with the rail.

The clips incorporate a robust coding system 9 for rapid automated verification of clip identification within potentially low levels of confidence for individual clips, for example a group of holes, recesses, reflective materials, metals, magnets or other easily detected items whose arrangement can be readily and repeatably translated as all or part of the clip's serial number. Retro-reflective optical sensors could be used on the clips.

The coding system need not uniquely identify each clip, since a bar code reader (for instance) equipped to read sufficient bits for this purpose might not operate fast enough to read clips"on the fly". However, using only a short bit sequence which can be rapidly read, the coding system 9 is sufficient to enable a high probability of precise clip identification based on pre-knowledge of the actual or intended sequence of clips (by the central control computer system of the mail facility).

It would be feasible to replace the human readable barcode or edge mounted barcode with a cheap serial EEPROM. This could be read electronically.

Once items have been put on the track, in principle it may no longer be necessary to use the item identifiers, since their position in sequence on the track can be monitored by the control system of the sorting station to route them appropriately.

The clips may incorporate an outline profile or features 10 to assist their accurate location within a localised area, for example one or more holes, recesses, reflective materials, metals, magnets or other easily detected items whose arrangement can interpreted as a precise indication of the clip's location or orientation.

The clips may have other features that promote ease and efficiency of use. For example the clips may be slightly magnetic (so that they naturally stick together, which may make the movements on the track smoother). They may be shaped to nest efficiently.

Preferably, means are provided for decoupling all the collars to realise all the items simultaneously from their clips.

Connection Element The connection between the clip 6 and the postal item may be composed of one or more elements. The lowest element 3 of the connection between the clip and the postal item may be self-adhesive, and stuck directly to the item and/or, it may be held to the item by one or more short lengths of

pressure-sensitive self-adhesive tape 2 as shown. These self-adhesive tapes are likely to be transparent. The size, shape and number of tapes 2 and 3 may be varied as desired to adequately support postal items with a variety of shapes and weights. The arrangement of the tapes will have to remain compatible with all subsequent processes, for example the triangular void formed between the two strips 3 and the top edge of the item 1 may be used to support the item when it is later removed from the clip as described below.

Preferably, the item hangs from the middle of the widest edge which is compatible with the width of the sorting apparatus.

The tapes 2 and 3 may be fitted to one or more faces of the postal item. Where the tape 3 is a self-adhesive tape it may be folded back onto, or otherwise passivated by, itself, or another length of tape (not shown), to ensure that no undesirable adhesive surfaces are exposed once the tape is in place on the postal item.

The tapes 2 and 3 may also use for example colour, images, text or bar-codes to support postal services and applications such as advertising, service information and identification. The self-adhesive tape 2 may feature a "peelable"adhesive to allow it to be released easily by a human. The selfadhesive tape 2 may feature one or more tags (not shown), to assist its optional subsequent full or partial removal prior to delivery.

For peelable tapes, it would also be possible to use a sacrificial layer of tape (which is non-peelable) as a backing, to which the peelable tape is adhered.

The upper elongate suspension element 5 of the connection between the clip and the postal item is potentially reusable or may be composed of one or more thin narrow tapes or strings (not shown). In the example shown, the connection is implemented as a tapered plastic strip inserted into the body 6 of the clip and wrapped around the loop of tape 3. The doubled-over end of the strip may be effectively locked in place by an optional collar 4 that can slide up and down the strip. A clip and strip is shown in Figure 2 ready to receive the loop of tape connected to an item. Other connective arrangements are possible (not shown), for example the connective strip may incorporate a hook or slot or may grasp the tape like tweezers, or with overlapping teeth.

The collar 4 is shaped to reduce any tendency for items on a tape strips to rotate beneath their clips.

The collar 4 may incorporate lugs 11 easing the task of moving the collar up and down the strip 5 and other features that support the need to avoid the collar being accidentally released.

One or more of the elements 2 to 10 may be combined or integrated.

One or more of the elements 2 to 5 may be replaced by a thin disposable plastic structure (not shown). This structure would typically have an"A"or "8"shaped section once in place between the item and the clip. This shape provides a separate upper enclosure which allows it to be secured to the item at the bottom and also to be appropriately looped over the clip so that it can be unhitched or cut free of the clip whilst the upper enclosure still forms a continuous loop of material immediately above the item by which the item

can be carried. This connective structure may be supplied in a continuous strip with tear-off portion that only need be separated later, to enable a single connector to be separated for use as part of the item mounting process.

Where the connective tape 2,3 is to be applied before item processing, the tape itself may represent the proof of payment (i. e. stamp). It may then be applied from a franking machine by a customer or at a Post Office.

Transport Rod Where postal items attached to clips are to be transported or stored away from the rails on which most processing occurs, and prior to subsequent mechanised handling, the preferred vehicle is a rod 13. The main body of the rod 13 is a strip of plastic or metal track 21 whose cross-section, as shown in Figure 4, is compatible with the void in the centre of the top of the clip 6. The working surfaces of this track may have a low friction coating. The tracks could be made of plastic or metal (for example either anodised aluminium or Teflon coated steel). A two part track consisting of a low friction plastic sleeve or top surface over a metal frame could also be used.

Apart from the track section shown in Figure 4 (as circular), track having,"x"or"+"shaped cross section would also meet many of the requirements of the system since these, too, prevent side-to-side pitching or yawing or the clip on the track. Figures 12 and 13 show alternative clip/track cross-sections.

Attached to the track are two or three further track mounting elements 12,14 and 15 that may be quickly unbolted if they or the track are to be

replaced. Any of these elements may incorporate non-volatile electronic (or other) memory devices for identifying the rod and storing information relating to the clips, postage items and associated processing activities. The interface to interrogate or write to these memory devices could be through direct electrical contacts (not shown) or via a wireless communication medium using for example radio frequencies, visible or infra-red light or electromagnetic induction.

One end of the rod has a handle assembly 12 that incorporates a latch 19 for securing the rod to a machine or stand. This handle also incorporates a buffer/end-stop 18 that is disengaged by the action of mating the rod with a machine to enable it to receive items from, for example, another aligned track, or by insertion onto the track by a human, and is engaged on the removal of the rod to prevent items coming off accidentally.

The other end of the rod also has a handle assembly 15. This handle has its own buffer/end-stop 17. This handle also has a small human interface 16 that permits the transfer of information and commands relating to the processing of the rod, postal items, clips and the systems with which it interacts.

A third element 14 may be used to provide another carrying handle or additional support for the rod when installed in a machine.

The rod may incorporate soft rubber (or the like) braking/locking strips 20, or toothed strips (not shown in Figure 3) running along its length and engaging with the clips, that reduce any tendency for the clips to slide up

and down the track and that also hold down the collars 4 on clips to prevent their undesirable release. When the rods are secured within a machine the braking/locking strips 20 would be retracted into channels on either side of the rod's position thus not interfering with the flow of clips on to and off of the rod.

All the main elements 12,14 and 15 attached to the rod 13 may incorporate lugs 23 for supporting the rod within a machine or storage frame.

The rod's human interface 16 may incorporate a number of elements, for example high visibility indicators 22 of bright and/or flashing coloured lights, switches and push-buttons 25, a graphical or alphanumeric display area 24, a unique bar-code 26 and a small speaker/sounder or similar audible transducer (not shown). The human interface 16 would typically incorporate its own power source (not shown) that may be recharged while the rod is mated with any suitably equipped system. Apart from providing information regarding the current state of the rod and its associated postal items, it may also be used to relay information for or from other elements of the sorting system as convenient and in a flexible manner.

The rods 13 may incorporate sensors for clip detection or identification.

If there is a requirement to daisy-chain rods end-to-end during loading or unloading activities the rod's human interface 16 if present would be mounted above the rail and this end of the rod would be modified to resemble the features of that part of the sorting machine that normally mates with these

rods. An additional buffer/end-stop similar to that of the conventional rod 18 would also be incorporated into the handle.

Robust Delivery Device Prior to delivery it may be desirable to transfer the items to a more robust transport device. Typically, for delivery from a vehicle or trolley, such a system may be a simple metal bar (not shown)-optionally including a human interface similar to 16. This bar would be inserted into the void in the lower part above each item so that they could be removed from their clips 6 without losing their current place in the sequence of adjacent items.

Alternatively the items could be transferred to a compatible delivery pouch as shown in Figure 6. The delivery pouch would comprise a bandolier strip 28 that could be opened to allow one end to be passed through the void in the loop of tape above each item so that they could be removed from their clips without losing their current reference place in the sequence. The bandolier 28 would then be closed back into a loop by re-fastening its two ends together, to prevent the items coming off, and the items wrapped in a soft weatherproof cover 27. The cover may also have spare room to accommodate additional postage items or other items to be carried by delivery staff. Either the cover or the bandoleer may optionally including a human interface similar to 16.

To support the bandolier 28 as it is pushed through the loops above the items, it may be formed with a pocket or as a hollow tube so that it can be temporarily strengthened with a long narrow metal insert. Alternatively the

bandolier 28 could be pulled through the loops by the retraction of a guide rod.

Once the item's sorting processes are complete the clips 6 are no longer required and they may be removed and reused if desired. Empty clips 6 may be transported and stored on rods 13 before being reintroduced to a sorting machine.

Sorting Nodes The sorting-nodes in the sorting and sequencing machines rely on two types of diverters supporting either constrained/indexing or simple flow control.

Constrained-Indexing Node Figure 7 shows the most significant element in an example of a constrained/indexing sorting-node according to one embodiment, where a series of track-stubs 31 may be used to provide lateral movement of a clip between several lengths of track. Each track-stub resembles a narrow slice through a length of standard track. The thickness of the section 29 bearing the track-stubs is designed to be compatible with the thickness of the clipsalthough they need not be the same thickness e. g. several track stubs may support a single clip. Typically an item would initially arrive and be presented on the central stub.

The sorting operation could then shift the clip to one of the outside track-stub positions. The track-stubs would be arranged such that another stub takes the place of the original stub in the central position. This

arrangement allows the track-stubs to form a continuous track feeding two or more output stages.

The number of output stages that can be sorted to in a single operation is effectively only limited by the number of separate track-stubs on each individual section 29. The number of clips that can be sorted simultaneously is effectively only limited by the number of adjacent sections of track-stubs.

Once the sorted items have been moved on to the next stage in processing, the sections of track-stubs would return to their original positions before receiving the next batch of items to be sorted.

The section 29 bearing the track-stubs may also incorporate guides 30 to prevent clips on adjacent sections from coming off. Both the track-stubs and guides may incorporate sensors for detecting the presence and position of clips and the position of the section of track-stubs itself. Through-beam optoelectronic sensors could be integrated into the section of the track stubs either directly or indirectly by making use of simple waveguides connected to remote sensors.

The section 29 bearing the track-stubs may be moved horizontally by simple linear actuators e. g. solenoids or pneumatic actuators (not shown).

Alternatively the track-stubs may be wrapped round in a circle to form the teeth of a flat disk, (as shown in Figure 16) in which case they may be indexed mechanically or rotated using electromagnetic or piezoelectric motors (not shown).

A sorting-node (not shown) may use one or more solenoids directly to push clips sideways onto a parallel section of rail. Having pushed the clip sideways, a simple spring-loaded plunger would ensure that the clip joins the new rail correctly.

Flow Control Sorting Node Figure 8 shows a top view of a sorting-node relying upon the principle of flow control. Figures 14 and 15 provide further details. Typically clips (not shown) would be flowing from left to right, either under gravity or by direct mechanical force, and would be sorted to one of two or more (not shown) outfeeds on the right of the figure. The infeed track 36 may be flexed or hinged to allow it to mate adequately with the outfeeds-in this case the currently selected outfeed is marked 34. The necessary movement of the track could be achieved in a number of ways. In this example the track is flexed about a pivot point 35, which is connected to two actuators 33 by a short rod 32. The progress of clips may be monitored by sensors 102 (see Figure 14), and the movement of clips at the join between the tracks may additionally be controlled by a gate provided by actuators 104 that halts the clips during lateral movements of the track. Where necessary other actuators may be present to promote or ensure the desired movement of the clips between tracks for example to ensure that clips make adequate progress or move quickly through specific parts of the sorting mechanisms. The sensor requirements to support the potential to interpret any coding on the clip for

example the barcode 7, or more likely the complementary coding system 9, may be integrated directly into the sorting node (or just before it on the track).

Bidirectional Node When desired, and where supported by adequate sensors and compatible actuators, the motion of the clips through each sorting node may be bi-directional. Bi-directional working implies that sorting proceeds in stages, phases or passes that are to be completed before the direction of sorting may be reversed.

Sorting Machine Figure 9 suggests a possible layout for a sorting machine utilising the features already described. The machine incorporates a range of infeeds designed to cater for the following categories of postal items: collection mail 40, packets (not shown), large flat items 44, letters 42 and any items already fitted to clips 43.

The details of the infeeds are not shown ; but in each case, except for those items that are already fitted to clips, the primary goal is to fit the items to clips. An item may require the identification or alteration of its significant attributes. The item's addressee information may need to be read and interpreted (by scanning with an electronic camera and then performing Optical Character Recognition or human data input into a control computer of the mail processing centre), and any stamps or indicia that it bears may need to be read and cancelled. The order in which these operations are performed is not important ; and these operations may be performed in a machine section

41 before or after the items are fitted to their clips and subsequently handled almost exclusively on rails.

It is anticipated that items arriving already fitted to clips will require fewer operations to determine or alter their attributes and may simply bypass any unnecessary processing stages. The information associated with these pre-constrained items may accompany them stored electronically in their rods or clips or it may be transferred separately. In each case, confident verification of the sequence or identity of individual items may be obtained by positively identifying a rod, item or clip.

The infeed system may ensure that items are given an orientation that supports the delivery process and space-efficient transportation.

To ensure that the relevant and adequate information regarding each postal item has been correctly associated with the currently known position and identity of its clip the attributes of some clipped items and the identity of their clips may be reviewed. The scope of these activities may be varied in accordance with for example the origin and history of the items, their prior connection to clips plus the source and quality of the information regarding both items and clips.

Loose bundles of letters or other awkward items may be transferred to clear plastic wallets to be handled like packets. With the items removed the plastic wallets may be reused. Similarly items may have an additional strap or ribbon fitted to support them during handling.

Postal items may be presented in reusable envelopes. Reusable envelopes may incorporate an equivalent to the loop of tape 3. Reusable envelopes may be made of a clear plastic and may use for example colour, images, text or bar-codes to support postal services and applications such as advertising, service information and identification.

The number and combination of infeed types is designed to match the desired input profile for the sorting machine i. e. the relative volumes and types of postal items over time.

Infeeds and Initial Processing Although the details of the infeeds and initial processing sections are not shown the following features can be identified. Before or after fitting items to clips they may be weighed and passed in front of a series of cameras that are used to record images of each item. These images may be used to identify attributes such as addressee, sender, postage payment, postal service and barcodes or other existing coded information. This image interpretation may be performed automatically by computer or with human assistance or may be achieved by manual code entry.

The information recorded about the postal item may be used to determine its destination or route in each subsequent sorting process.

The task of recording item attributes, or coding, and fitting items to clips may be performed manually-particularly for postal items with nonstandard shapes.

The need to alter an item's attributes is normally limited to a need cancel stamps or printing information for example date and time and the machine's identity. This may be achieved by passing the items through a printing sub-system and subsequent drying section to prevent smudging.

Other alterations to an item's attributes are associated with mail redirection and other postal services. These services generally affect the desired routing of the item, but they may also require the addition of common or personalised labels to support the activities of delivery staff. Any commonly used labels may be pre-printed and any personalised labels may be printed on demand using blank or pre-printed label stock. Labels may be applied automatically or at manual work areas adjacent to the sorting machine (not shown).

Although the details of the systems for fitting items to clips are not shown the following features can be identified. Items would be presented either loose or in stacks. Loose items may be segregated using a conventional slatted drum arrangement and pick-off rollers. Stacked items may be isolated by friction from belts or rollers being assisted by a vacuum if necessary. Where the size or outer wrappings of items precludes the use of friction for singulation (isolation) simple suction devices may be used to pick up and separate or transport individual items before they can be fixed to clips and rails.

The form of the connection between the postal item and the supporting rail need not be the same for all items. Several forms of this connection may

be employed for a range of different item types for example flimsy items, letters, large flat items and packets. Predetermined lengths of tape 3 and selfadhesive tape 2 may be pulled from reels and applied to the item using light pressure. A clip 6 that may already be connected to a rail (not shown) would capture the loop above the item formed by the clear plastic tape 3.

The clip's unique identification and relative position on the rail may be identified at any convenient stage in its processing for example when the empty clips are loaded into the machine, when the clips are attached to items or at the same time as the items attributes are being determined.

In the case of flimsy items, the connective tape may be used to add to the weight or stiffness of the item on the clip.

Sorting Sorting items will generally proceed in machine module 39 where repeated branching of the track is achieved. Each branching of the track supports two or more sub-divisions. Items arriving from the various infeeds may have been combined into a single flow or may be handled by switching in turn between the buffered outputs of each infeed as appropriate.

Subsequent sorting processes may be performed largely in parallel thus reducing the significance of any high throughput requirements that exist for the initial stages of item sorting.

The sorting module 39 may maintain the items slightly above head height for the majority of their travel to the outfeeds, thus allowing efficient

use of the floor space beneath for storage, gangways or other equipment modules. The sorting module branches towards a series of outfeeds 37.

Outfeeds Each outfeed may be fitted with some buffer storage and a mechanism for transferring items to rods 13. Outfeeds may incorporate semi-permanent links (not shown) to other machines. Outfeeds may also form the basis for extending the number of outfeed selections on a machine by attaching further sorting modules 38 and outfeeds. Outfeeds 37 may be tiered to increase their volume and space efficiency. In this example, the outfeeds have three tiers each capable of handling rods containing items whose maximum size is approximately that of an A3 item (420mm high by 297mm wide) in a loose fitting envelope.

Although the details of the sorting module 39 are not shown the following features can be identified. The sorting module may contain a number of sorting nodes based on the principles shown in either of Figure 7 and Figure 8. As the sorting system branches towards the outfeeds 37 so more sorting nodes are required at each stage although their throughput requirements may be significantly reduced. The passage of clips at and between these sorting nodes is likely to be directly driven by electromechanical means for example worm drives, ratchets, toothed belts or small drive wheels mounted alongside the path of the clips. It is feasible that the movement of clips is cycled between driven up-hill stretches followed by un-powered down-hill slides.

The transfer of items between buffer stages or between a buffer stage at an outfeed 37 and a rod 13 may not require individual control over clips. The single action of a solenoid (not shown) could control the release of all the items currently present in the item buffer (not shown).

Where items are buffered at outfeeds they need not transfer items to a dedicated outfeed or rod. Several buffers may share the mechanisms for supporting a rod whilst it receives their current store of items.

Information, signals and power may be physically transferred between the outfeed and the rod whilst the rod is connected to the machine. Without this physical contact only wireless information transfers are feasible.

The sorting machine may inject empty clips to improve the efficiency of some of its processes for example to create space around awkward items or to assist in clearing the machine of clips still containing items.

Figure 9 shows a sorting machine that incorporates all the features necessary to complete a single sorting pass on a wide range of postal items.

However, the same principles could be employed to create a sorting machine (not shown) where a larger number and variety of infeed, sorting, processing, buffering and outfeed modules are connected in a flexible and robust manner capable of performing automatic multi-pass sorting of huge numbers of items, with little or no human intervention, from the initial culling of collection mail through to the final sequencing and preparation of items prior to delivery.

Such a system would be organised to tolerate a certain number of individual

module failures whilst still delivering an acceptable overall level of performance.

Each delivery point requires its own selection, but it is not normally necessary to make any physical distinction between successive delivery points. Delivery staff immediately prior to each separate delivery normally examine each item's address and perform the task of identifying the correct items for each delivery point, from a continuous sequence of items.

Removable panels of a coarse wire mesh (not shown) beneath the sorting module 39 would permit the rapid identification of any items falling from the rails. This task may also be supported by the use of back-lighting, additional sensors or cameras.

Although Figure 9 shows an integrated sorting machine, a standalone infeed system (not shown) could be used for simply attaching items to rods and optionally recording information to be stored in or later transferred with the rods. Similarly the tasks performed by the infeed system may be performed by mechanisms integrated into mail preparation machines (not shown) where they would follow the final enveloping or addressing subsystem.

Sequencing Figure 10 shows an internal view of portions of a machine for correctly sequencing the items prior to delivery. The figure shows a sequencing machine that composes 6 sorting elements. All six sorting elements may be rocked by the action of their common connection 45 to a

single actuator 50. Pillars 48 support the individual sorting systems whilst supplying power and control signals to their respective sorting mechanisms 49.

Each sorting mechanism comprises two sorting nodes as shown in Figure 8 in a mirrored arrangement 46. This arrangement allows items to pass, under gravity, between individual arms 47 of each sorting element to either of the pair of arms on the other side of the sorting node. The actuator 50 may be used to alter the angle of the sorting element and thereby reverse the direction of the natural flow of the items on their clips.

Thus, items may be re-sequenced as follows: If the initial sequence of items at a first of two nodes is A, C, B and the desired sequence is A, B, C, then item B is routed to the left hand branch of a second node, and then item C to the right left hand branch of the second node. Then the direction of flow between the two nodes is reversed, and item B is switched back to the first node, followed by item C. Obviously, the process can be repeated as necessary to execute sorting into arbitrarily long sequences as required.

Figure 10 also details how one or more removable rods 13 may form the tips of the accessible arms of the sequencing machine. The supporting structures for the rods 13 and actuators to enable full control of the clips and sorting nodes are not shown. If each selection is given a binary code, sequencing proceeds by sorting clips to the progressively more significant binary digits in this code starting with its least significant bit.

It is feasible to alter the timings of any machine processes, for example scanning, cancelling and sorting, in response to or with prior knowledge of aspects of the items being handled to improve the quality or efficiency of the overall operation.

Figure 10 shows the perspective view of an arrangement with a total of 6 sorting elements in three tiers with two sorting elements working backto-back on each tier. Further sorting elements could be positioned in parallel to such an arrangement and still be rocked about their pivot points by links to a single actuator. These parallel sorting elements may share common supporting pillars 48. Easy access to the sorting nodes of all the sorting elements is desirable for maintenance and in case of faults.

An adequate sorting element (not shown) can be achieved by connecting a single removable rod 13 to a single sorting node as shown in Figure 8 where it feeds the two permanent arms 47 of the sorting element. In this case the sequencing of the clips 6 on the rods proceeds by repeatedly transferring the clips on the rod to one of the sorting element's arms 47 on the opposite side of the sorting node. The groups of clips are then returned to their initial rod before the next such sorting pass. With each such successive pass the sequencing system is capable of sequencing the items to at least twice as many selections; and each such selection may include an arbitrary number of clips up to the full capacity of the rods.

Equivalent sorting systems could be constructed where each side of the sorting system has a larger or different number of arms 47. Generally, the

greater the number of available arms, the fewer passes required to support the desired number of selections.

The requirements for operating the sequencing system detailed in Figure 10 are compatible with its use in a range of adverse operating environments including those with limited energy availability and poor physical stability for example as may be found in a moving vehicle. Thus, sequencing can take place in a delivery on the way from the sorting office to the delivery addresses, or between offices.

Any sorting system would require embedded electronic systems for control and monitoring. Centralised and remote computer systems are also likely to exist within the working area containing the sorting systems for efficiently performing tasks such as image processing, manual data analysis and data entry plus information storage and dissemination.

The machines portrayed in Figure 9 and Figure 10 would probably use manual labour for loading and unloading both items and rods; but automated or mechanically assisted loading, removal and transportation of items and rods is a viable option (not shown).

The task of moving rods 13 carrying items between machines may be achieved by wheeled trolleys (not shown), similar to those currently in use for transporting mail in trays. These trolleys may incorporate display and interface units similar to those on rods 16. Internally, the trolleys may be fitted with a series of brackets for supporting rods making it possible to remove rods at the bottom of the trolley without removing those above. The

vertical separation of these brackets would reflect the fact that the items on the rods can generally become flattened when supported from below.

Machine sections and sub-assemblies could conveniently be identified using bar-codes-to aid maintenance activities.

All clips are uniquely identifiable and their movements through the system can be determined exactly. Therefore any maintenance activities for the sorting equipment could be based on a precise history of component and sub-assembly usage.

Machine vision or simple sensors could be used to identify and reject any items that are not properly suspended from their clips and rails.

A detailed inspection of a machine may be made by a compact telemetry package (not shown) being handled like a conventional postal item. This would incorporate cameras and other sensor systems capable of identifying and storing information regarding machine anomalies or transferring this information via wireless to a diagnostic system for analysis.

A similar package incorporating a vacuum cleaner or blower could be used to clean the machine.

Figure 11 shows schematically the processing of operations of the sorter. From the infeed, items go through a plurality of sorting points to a number of outfeeds (only two sorting points are shown). For example, to sort into 2048 delivery points, using nodes which can switch only between two output lines, only eleven stages would be required. The switches stages therefore"fan out"in a triangular arrangement, with the output of each

switching node being connected to a further switching node. Of course, for switching nodes capable of switching between more than two outputs, the number of stages required is considerable fewer and the apparatus can be made more compact.

Where each switching node is arranged to switch between two outputs, a simple binary address can be used to route items through the switch, with each switching node responding to the next bit of he binary address.

Summary of Processing To summarise, according to an embodiment of the invention, referring to Figure 17, after collection (step 202) the address of a postal item is read (step 204) and inputted to the central control computer of the mail processing facility. In step 206, the postmark is cancelled. In step 208, the item is mounted to a clip 6, by attaching the support structure to the item, and the item to the clip, and the clip to the rail.

In step 210, the item is transported along the rail to an infeed of the sorter apparatus of Figure 9, and then in step 212, it (together with other items) is sorted, by passing the items through successive switching nodes comprising stages of the sorting apparatus. At each stage, the central control computer instructs the switching node as to which output path to switch the item to, either in response to the order of occurrence of the item, or in response to the identity of the identifier on the item being read by a sensor at the node.

Finally, at the outfeed of the sorter, the item (together with others in the same batch intended for the same local area), are removed on a section of removable track, which is replaced by empty track, and transported using a transport rod 13 to the sequencer machine in step 214. The sequencer machine comprises a bi-directional switching node having input and output paths and therefore being capable of sorting the items into an order.

The sorting machine may either be provided at the mail processing facility, or may be operated remotely (for example in a van). In the first case, the operation of the sorter in successive switching operations is controlled by the central control computer, which knows the identity of the items and their initial order, and their desired final order based on delivery address.

Alternately, where the sequencer is mounted in a delivery van, the initial order and final order information is downloaded from a central computer into the control system of the sorter, which then continues to perform the sequencing operation remotely. In this way, time which would otherwise be spent merely in transporting items can be utilised to sequence (in step 216).

Finally, in step 218 the items are delivered in the sequence, having first been removed from the sequencer using a rod and inserted into the robust delivery device of Figure 6.

Other Embodiments and variations Whilst embodiments of the invention have been described, it will be understood that many variations and modifications could be made. The present invention extends to any and all such variations.

Although in preferred embodiments the routing of individual items and associates with rods is handled by a central processing computer of the mail processing facility, it would also be possible for the rods or the clips themselves to be loaded with their full routing requirements following an initial scan by the central computer which determines the destination of the item. Then, at each stage, the routing nodes could be controlled in response to a scan of the data carried on the item, rather than being controlled by the central computer. This would reduce the load on the central computer, and would also enable routing to continue in the event of a failure of the central computer system.

The majority of item movements would be performed under gravity but"uphill"movements or sorting control could be achieved by moving the clips forward using a ratchet mechanism operating on the top or sides of the clips, or a worm drive acting on either side of a central ridge in the track.

Alternatively, clips could be moved through the sorting nodes by small drive wheels operating on one or both sides of the clip, which are preferably spring loaded to improve their contacts with the clips and make diverter operations smoother (equally, opposable solenoids could be used).

Whilst the items to be sorted are thinner than the depth of the clip, the pitch between items is controlled by the depth of the clip. It would also be possible to use the present invention with thicker items, in a number of ways; firstly, the thickness of each item could be measured directly and used to control the actuation time of the switching nodes ; or secondly, the thickness could be extrapolated from the rate at which an item passes a point in the machine.

The cameras used to perform sensing may be cheaper than with existing mail systems since they are only required to operate at slower speeds.

For the avoidance of doubt, protection is hereby claimed for any and all novel subject matter and combinations thereof disclosed herein.

Claims

1. A postal processing system for processing items of post, which comprises a transport system arranged to move items of post in a transport direction, the transport system comprising a guide extending in the transport direction, and a plurality of carriages mounted to the guide, each item being mounted to a said carriage.

2. A system according to claim 1, in which the transport direction is generally transverse to the plane of the items of post.

3. A system according to claim 1, in which the guide has a downwards slope along at least part of its length.

4. A system according to claim 1, in which the items of post are suspended from the guide.

5. A system according to claim 1, in which the guide and the carriage carry mutually interengaging features.

6. A system according to claim 5, in which the features are shaped to prevent the carriage yawing transverse to the transport direction.

7. A system according to claim 1, further comprising a uniquely coded identifier associated with each item, and sensors for reading said identifier for each item.

8. A system according to claim 7, in which the identifier is carried on the carriage.

9. A carriage for carrying items of post on a guide, for use in a system according to claim 1, comprising an engagement portion having engagement features shaped to engage corresponding features on the guide, and an attachment portion attachable to a postal item.

10. A carriage according to claim 9, in which the engagement portion comprises a detachable and re-usable clip.

11. A carriage according to claim 9, in which the attachment portion is disposable.

12. A carriage according to claim 9, in which the attachment portion comprises adhesive tape.

13. A carriage according to claim 9, comprising handling features permitting the carriage to be carried away from the guide aligned together with neighbouring carriages.

14. A carriage according to claim 13, in which the handling features define an aperture through said carriage in said transport direction.

15. A carriage according to claim 9, further comprising a coded identifier.

16. A carriage according to claim 15, in which the identifier comprises an optically readable identifier.

17. A carriage according to claim 16, in which the identifier comprises a plurality of retroreflectors.

18. A carriage according to claim 9, further comprising an alignment indicator.

19. A clip for a carriage according to claim 10.

20. An attachment portion for a carriage according to claim 11.

21. A roll of patterned adhesive tape comprising a plurality of attachment portions for a carriage according to claim 12.

22. Postal arranging apparatus for arranging items of post, comprising: a guide extending in a transport direction, and arranged to be able to carry a plurality of carriages mounted to the guide, each item being mounted to a said carriage; a switching point arranged to couple together one or more first paths to a plurality of second paths, each path comprising a portion of said guide; and an actuator arranged to select which of said second paths said first is connected to.

23. Apparatus according to claim 22, in which each switching point consists of one first path, to which said items are supplied, and a plurality of said second paths, so that said items are distributed between said second paths under control of said actuator.

24. Apparatus according to claim 23, in which each switching point consists of two said second paths.

25. Apparatus according to claim 22, in which each switching point consists of more than two said second paths, and a movable intermediate member arranged to collect items from a first path and to route them to a second path.

26. Apparatus according to claim 22, comprising a plurality of said switching points, the first paths of some being connected to the second paths of others, so as to define a structure fanning out from an input path of said apparatus to a plurality of item output paths of said apparatus.

27. Apparatus according to claim 22, in which each switching point consists of a plurality of said first paths and a plurality of said second paths, and is arranged to be able to route items bidirectionally, selectively from a first path to a second path or vice versa, under control of a direction control device.

28. Apparatus according to claim 22, in which the guide has a downwards slope along at least part of its length.

29. Apparatus according to claim 22, further comprising a drive system to drive carriages through the or each said switching point.

30. Apparatus according to claim 27, in which the direction control device is arranged selectively to tilt said switching point with either said first paths below said point and said second paths above or vice versa, so as to select whether a said item passes from a said second path to a first or vice versa.

31. Apparatus according to claim 27, further comprising a memory storing data defining the order in which said items are present, and the order in which they are to be sequenced, and a control unit controlling the direction control device in dependence upon the data.

32. Postal item transporting apparatus comprising: a guide extending in the transport direction and suitable for carrying a plurality of carriages, each item being mounted to a said carriage; detents at the ends of the guide to retain the carriages thereon; and a memory retaining coded data indicating the identity of the apparatus and/or the items.

33. Apparatus according to claim 32, further comprising a display for displaying said data.

34. Apparatus according to claim 32, further comprising a wheeled trolley supporting said guide.

35. A method of postal item arranging comprising carrying postal items transversely to their plane along a constrained guide path.

36. A method according to claim 35, comprising carrying said postal items along a downwards sloping guide path.

37. A method according to claim 35, comprising passing said items through a plurality of sequential branch nodes in the same direction, to sort said items into subsets.

38. A method according to claim 35, comprising passing said items through at least one branch node in alternating directions, so as to re-sequence said items.

39. A method according to claim 38, comprising performing said resequencing in a moving vehicle.

40. Apparatus and/or methods substantially as herein described with reference to any of the accompanying drawings.

41. Postal item sorting and sequencing mechanisms utilising uniquely identifiable clips and connective structures directly between postal items and rails.

42. Clips and connective structures as claimed in Claim 41 wherein a potentially reusable clip assembly is used in conjunction with a disposable connective tape assembly.

43. Clips and connective structures as claimed in Claim 41 wherein a potentially reusable clip assembly is used in conjunction with a potentially reusable envelope incorporating a connective tape assembly.

44. Postal item sorting and sequencing mechanisms as claimed in Claim 41 wherein rigid rods are employed for receiving, handling and transporting the clips whilst retaining their physical position relative to adjacent clips plus support for association with information related to clips and associated postal items both individually or as groups.

45. Postal item sorting and sequencing mechanisms as claimed in Claim 41 wherein flexible straps are employed for receiving, handling and transporting the clips whilst retaining their physical position relative to adjacent clips plus support for association with information related to clips and associated postal items both individually or as groups.

46. Postal item sorting and sequencing mechanisms as claimed in Claim 41 wherein individual clips successively pass through potentially reversible switching and sorting nodes between successive buffer or transfer stages.

47. Postal item sorting and sequencing mechanisms as claimed in Claim 41 wherein groups of clips successively pass through potentially reversible sorting nodes between successive buffer or transfer stages.

48. Postal item sorting and sequencing mechanisms as claimed in Claim 41 wherein each postal item is connected to a clip and rail appropriately for its relevant postal attributes and prevailing processes for determining and potentially altering these attributes.