BACKGROUND TO THE INVENTION In postal sorting offices, apparatus is used by the postal workers for efficiently sorting postal items.

EP 0635316 shows postal sorting apparatus which comprises a rigid main support frame. A rectangular work surface area, and above it, a plurality of rows of postal item trays are attached to the main support frame, usually by screws or bolts. The worker may transfer postal items into the trays manually for sorting purposes. The work surface area enables the postal worker to arrange the postal items before sorting.

It is possible with these systems to attach one or two supplementary rectangular wing units, at an angle, to the sides of the main support structure so that further postal item trays may be placed within reach of the postal worker. These supplementary units are attached using screws or bolts, in a semi-permanent manner.

In this known system, the support frame can be levelled against the floor, and the height adjusted to an ergonomically or otherwise suitable level, by manually extending screw-in feet at the bottom of each of the four legs of the frame.

A problem with this previously proposed system is that it is difficult and time consuming to dismantle the sorting apparatus, and reassemble it or consign it to store. As a result it is difficult to move the apparatus from one location to another once it has been assembled. A further problem with this previously proposed apparatus is that it neighbouring postal sorting stations cannot easily be connected together, or adjusted as one for height.

Embodiments of the present invention have been conceived with the aim of alleviating these problems.

STATEMENT OF INVENTION In pursuit of this aim, the embodiments of the invention provide postal sorting apparatus as set out in Claims 1,16 and 17. Generally speaking, embodiments of the present invention comprises a stand-alone modular unit with a support structure and a work surface area for sorting postal items, which can be infinitely extended into a postal sorting system by adding further such modules as desired. Thus, it offers much greater flexibility than in known sorting systems.

Since the postal trays of preferred embodiments are assembled from interconnected preformed components and are stackable, they are effectively self supporting and do not need to be hung form substantial fixed frames of the type disclosed in the aforementioned European Patent Application.

Preferably, the modular unit conforms generally to a segment of a circularly symmetrical shape; that is, it tessellates with other identical units to provide a rotationally symmetrical shape (such as a circle or, more conveniently, an octagon). Although this could be achieved with two or more modules of complementary shape, it is preferred to provide a single module tessellating with others identical to itself, so as to avoid the need to make and stock multiple units for use together.

Preferably, the outer profile of the module comprises (or approximates) an octagonal segment consisting of a side of the octagon flanked by two half-sides thereof, and preferably the inner surface of the worktop comprises a circular arc.

Preferably, each module comprises a height adjusting mechanism which simultaneously adjusts the height of the worktop (and, preferably, the rest of the unit too) at a plurality of support points of the module. This greatly increases the ease of adjusting the height of a single module relative to the known system.

Preferably, each module comprises means for coupling the height adjusting mechanism to that of other modules to which it is connected, so as to permit all such connected modules to be height-adjusted from a single

point, at the same time. This makes it practically possible to interconnect multiple modules into an extended system with height adjustment, which would have been impractical in the prior art. The height adjustment may be manually actuated, or electrical actuators may be provided.

One particularly preferred embodiment of the invention provides postal item sorting apparatus comprising a plurality of interconnectable modules and a height adjustment system operable to adjust the height of all interconnected modules from a single adjustment point, wherein each of said modules comprises a work surface and a plurality of postal item trays mounted one on top of another on said work surface to form at least one tower of trays.

Further objects and advantages of embodiments of the invention will be apparent to the skilled reader from the following description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS Specific embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure la shows a plan view of a pair of interconnected modules according to a first embodiment of the present invention; Figure lb shows a front view of the pair of interconnected modules according to the first embodiment; Figure lc shows a side view of a pair of interconnected modules according to the first embodiment; Figure 2 shows a cross sectional view of the lifting arrangement according to one part of the first embodiment; Figure 3 shows a cross sectional side view of the gearbox according to one part of the first embodiment; Figure 4a shows a plan view of the gear system according to one part of the first embodiment; and

Figure 4b shows in greater detail part of the gear system according to Figure 4a; Figure 5 shows an example of a first modular arrangement according to the first embodiment; Figure 6 shows an example of a second modular arrangement according to the first embodiment; Figure 7 shows a shelf unit according to the first embodiment; Figure 8a shows a front view of a second embodiment according to the present invention; and Figure 8b shows a side view of the second embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The preferred embodiment comprises a plurality of modular sorting units making up a sorting system. In this embodiment, each of the modules makes up half of a sorting unit. Thus, a minimum requirement for a system, according to this embodiment, is two modules. Further individual modules (or pairs of modules making up units) can be added to make up larger systems.

Figures la, lb and lc show different views of a pair of modules A, B.

Each module comprises a support frame 100, and a work surface area 1. The module support frames 100 are made from hollow section mild steel. Each module has a pair 3 of vertical steel legs 3 (3a and 3b), with the top of the two vertical legs being connected together with a horizontal support bar 101.

Each module in this embodiment has an outer cross section which comprises one eighth of an octagon, comprising two adjacent half sides of the octagon around one of its vertices.

At ground level, the support legs have an additional horizontal support bar 4 fixed to the outside surface of the legs. The lower horizontal support bar 4 has adjustable feet 8 fitted at either end. The feet 8 have a screw thread that is placed through a tapped hole in the support bar 4. The feet 8 may then

be adjusted to ensure that the frame is installed in a level position on a floor surface.

Two modules are interconnected providing four legs 3 that support the whole sorting unit. Pairs of module frames 100 are interconnected by a cross brace 5, which gives support to the whole frame structure.

Fitted to the top of the frame structure is the work surface area 1. The work surface area allows the postal worker to arrange unsorted postal items before they are placed into the sorting trays 2.

The work surface area 1 is made from 25 mm medium density fibre and is covered by a plastics laminated covering. The front edge of the work surface area 1 has a rubber mould fitted for comfort. The front edge follows a circular arc, shaped so that when two modules are connected the arc is continuous. This allows the postal worker to be situated equidistant from all postal item trays 2. The work surface area 1 is fitted to the top of the frame structure by known means, such as screws, bolts, glue etc.

The two adjacent work surface areas of interconnected modules are fixed together using fixing means such as round disk dowels and steel threaded clamps.

Lifting mechanism A lifting mechanism is provided for the sorting system, which provides a way of adjusting the height of all interconnected modules together.

Each module is provided with an adjustment point, and the height of all modules can be varied by utilising only one of the plurality of available adjustment points.

As shown in Figure 2, each vertical leg 3 of the frame is constructed of a mild steel hollow section. A length of aluminium extrusion 23 is inserted into each section, with the top of the aluminium extrusion 23 being attached to a steel bracket 22 that is in turn attached to the lower surface of the work surface 1. Within the aluminium extrusion is fitted a worm screw 21 which passes into a bevel gearbox 24.

The bevel gear box 24 works in the following manner as shown in Figure 3. The operator turns a removable handle 7, which in turn rotates gear 31. Gear 31 turns the central gear 32, which in turn rotates all other interlinked gears, for example gear 34. The central gear 32 has a vertical channel with teeth cut into it, running through the centre of the gear. The teeth in the channel interlock with the teeth of the worm screw 21. Therefore, when the central gear 32 rotates, the worm screw 21 moves up or down depending on the direction of rotation of the central gear 32. The gears are supported in a bearing system 33.

The linking of the gearboxes between the modules allows all interconnecting modules to be raised and lowered at the same time using only one adjustment point. Each module comprises two gearboxes, each arranged to drive a respective one of the legs 3.

A first 110 is positioned at the leg 3 adjacent the work surface (i. e. the "front"leg of the module). It has a four-way bevel system, which receives input power from the adjustment point via the input gear 31, and supplies output power to the second gearbox 112 via a hexagonal bar 36, so as to lift the second leg within the module. It also supplies output power to two lateral hexagonal bars 36 (labelled 114,116) which lead to respective joining points 42 towards the front of the side edges of the module (which mate with adjacent modules if required).

The second gearbox 112 is positioned at the leg 3 which is distant to the work surface (i. e. the"back"leg of the module). It has a three-way bevel system, which receives input power from the first gearbox via the hexagonal bar 36. It also supplies output power to two lateral hexagonal bars 36 (labelled 118,120) which lead to respective joining points 42 towards the rear of the side edges of the module (which mate with adjacent modules if required).

As shown in Figure 4, the lifting mechanisms of the separate modules are interconnected in the follow manner. The four-way bevel gear systems are connected together using a hexagonal bar 36 locked into a hexagonal

socket 35 as detailed above. Due to the fact that these hexagonal bars leave the gearboxes of adjacent modules at an angle to each other, it is necessary to interconnect hexagonal bars coming from neighbouring gearboxes using universal joints 41 at either side of each gearbox. The shafts running between the universal joints and the side edges of the modules run normal to the side edges. Thus, shafts to be coupled at adjacent side edges of neighbouring modules are aligned parallel and coaxial with each other.

The embodiment thus provides a non-rigid structure of interconnected gear systems placed beneath the tabletop of the sorting system. The hexagonal bars are all enclosed within a housing 37 to avoid any danger of entanglement.

Adjacent modules are interconnected by using the joining points 42, as shown in Figure 4. The joining points at the side of each of the modules each consist of a hexagonal socket. Additional short hexagonal bars slot into the sockets of adjacent modules and therefore fix them together.

Thus, by rotating the input gear 31 at any of the adjustment points, the rotation is transmitted via the bars to the bevel gears of adjacent modules (and thence on to any other interconnected modules) to raise and lower all legs 3 of all modules together.

The lifting mechanism provides postal workers with the ability to easily adjust the height of all interconnected modules from any one chosen lifting point, within a maximum stroke of 250mm. The lifting mechanism channels also give the structure added support.

Systems made from modules Due to the modular construction of the sorting system, several different arrangements may be implemented easily and quickly so as to utilise the available workspace.

For example, as shown in Figure 5, due to the arcuate front portion of the work surface area, it would be possible to have an almost circular arrangement of work surfaces that may be arranged at a convenient height for

the postal worker. A single worker can thus be located equidistant from the maximum number of postal trays.

Figure 6 shows an alternative arrangement that may be used, allowing several postal workers to use the system at the same time. In this arrangement, pairs of modules are connected in alternation, so as to create an infinitely extendable sinusoidal linear arrangement comprising a series of workstations on alternating sides of the system.

It will be apparent from the foregoing description of the raising arrangement that the two connection points 42 on each side of each module can be reversed, so as to allow one of the modules to be connected in the reverse sense to its neighbour (i. e. with its work surface facing in the other direction). It may be necessary in some embodiments to provide the connection points 42 with a rotation-reversing gearbox in this embodiment.

As each module is linked together a rigid structure is formed.

Postal tray towers and in-fills At the back of each module, at the left hand side and right hand side of each work surface area is located a postal item tray 2. The postal item trays 2 may be built up into a tower of multiple trays.

In-between the two towers of trays are placed sheet metal link in-fills 9 that provide vertical stability to the tray tower and frame. The sheet metal link in-fills 9 are attached securely to the work surface area 1 by a securing means such as screws or bolts. The in-fills 9 are also secured to each of the postal item trays 2 by way of push in fittings. It is also possible to incorporate in the in-fills items such as pencil holders, paper clip tubes and elastic band containers to aid the postal worker.

When two modules are positioned next to each other, in a central location at the rear of the two attached work surface areas, there are two tray towers, one situated on the right hand side of the left hand work surface area, the other situated on the left hand side of the right hand work surface area.

The two tray towers are secured together using a securing strap at the four topmost points of each tray. The straps are secured by way of push in fittings.

One particular advantage of embodiments of the invention is that the trays are effectively self-supporting, with individual trays being constructed from assembled preformed components which can be located in-and preferably interconnected or interlocked with-neighbouring trays of a tower.

This means that these embodiments of the invention are free from the rigid relatively restrictive frames of previously proposed systems.

Postal trays Each of the postal item trays, shown in Figure 7, is constructed from a rear panel 71, a base panel 72, a left side panel 78 and a right side panel 76.

These panels are made from a material such as a light durable plastic. The front edge of the base panel has a 35 mm concave plastic label holder 77 clipped to it. This label holder is rotatably adjustable so that the postal worker is able to move the label holder to enable the label to be read clearly.

The base panel 72 and the rear panel 71 have a slot arrangement system incorporated into them, so that it is possible to fit dividers into the slots 73 allowing any number of shelf divisions to be arranged in units of 10 mm. Slots 73 are cut into the panels enabling dividers, not shown, with lugs situated in matching positions to the slots to be push fit together. It is possible to remove and rearrange dividers and therefore allow for larger postal items to be inserted into a larger shelf division as required.

The top edge of each of the side panels 76,78 incorporates fixing lugs 74 that attach themselves to fixing points 75 on the lower edge of the side panels of the interconnecting shelf above it. The side panels also have vertically extending strengthening ribs (not shown) to ensure stability.

The lower shelf 72 is secured to the work surface 1 by a fastener, such as a bolt or a screw, via fixing points in the base panel of the shelf.

The self-supporting, interlocking, load-bearing structure of the shelf towers ensures that no main framework or sub-structure is required.

One further embodiment comprises a minimum of one stand-alone module. It is possible to have a single module as shown in Figures 8a and 8b, with a self-supporting structure having four legs, and a rectangular work

surface area. The work surface area is adjustable in height with respect to the support structure as described before. Each stand-alone module may be connected to other modules in the same manner as described above.

The present invention provides a system with a large degree of flexibility allowing one or more modules with a multitude of different layouts.

Each module is capable of being linked with other modules using one universal lifting arrangement, which can be operated from any one lifting point. This provides an easily adjustable and variable workspace.

Further Embodiments It will be apparent to the skilled reader that various modifications and variations may be employed in relation to the above-described embodiment without departing from the scope of the present invention.

It will be apparent to the skilled man that any number of legs may be attached to each module in any position. The legs may also be replaced by any other suitable support.

It will also be apparent to the skilled man that the work surface area may be of other shapes.

The trays could be as described in EP 0635316. Trays (and even a work surface) could also be provided at the rear of a module, to allow workers to operate on both sides of a module. It will further be apparent to the skilled man that the use of trays is merely optional and that any other form of postal item retainer or receptacle may be used.

It will be further apparent that any suitable material may be used for the material of the support structure, work surface area and trays.

It will further be apparent to the skilled man that any number of gearboxes may be used in any combination.

By way of example, modules could follow profiles other than octagonal ; for example, circular, hexagonal, heptagonal, and so on.

Electrical or other actuators could be substituted for the manual handle 7 to raise or lower the worktop. A single gearbox on each module could drive

all legs on that module. Flexible drive shafts could be used instead of rigid drive shafts interconnected at universal joints.

Sorting of items other than post is possible. We have also realised that some aspects of the invention are applicable outside sorting systems, to modular assemblies in general.

Many other variants are possible. Protection is hereby sought for any and all new matter herein and combinations thereof, whether or not within the scope of or explicitly enumerated in the accompanying claims.