WO2009043077A1

WO2009043077A1 - Modular conveyor system

Info

Publication number: WO2009043077A1
Application number: PCT/AU2007/001443
Authority: WO
Inventors: Nicholas Bent
Original assignee: Cies Pty Limited
Priority date: 2007-09-29
Filing date: 2007-09-29
Publication date: 2009-04-09

Abstract

A modular conveyor system including: a head conveyor unit having a front drive roller located adjacent a forward end of said conveyor unit; a rear conveyor unit having a rear idler roller located adjacent a rearward end of said rear conveyor unit; and at least one intermediate conveyor unit located intermediate the head conveyor unit and the rear conveyor unit; wherein, located adjacent to die junction of adjoining conveyor units, there is a common axle having located thereon both an intermediate idler roller in substantial alignment with a drive roller of an adjoining conveyor unit, in a first direction, and an intermediate drive roller in substantial alignment with an idler roller of an adjoining conveyor unit, in a direction opposed to the first direction, and wherein an endless drive chain operatively extends about the aligned drive roller and idler roller of adjoining conveyor units.

Description

MODULAR CONVEYOR SYSTEM

Field of The Invention

The invention relates to a modular conveyor assembly. In particular, the invention relates to (but is not limited to) such a conveyor assembly for use in conveying pallets.

Background of the Invention

Conveyor systems are widely used in industry, such as in factories, warehouses, distribution centres and the like, for transporting goods from one position to another.

Several types of conveyor assemblies are known, including 'roller^" conveyors and ' endless belt' conveyors. A typical roller conveyor includes a pair of parallel side rails joined by a series of transverse connector bars to form a rigid frame. In between the parallel side rails a plurality of cylindrical rollers arc located. These rollers are caused to rotate (in a particular direction) under the influence of one or more motors. The uppermost portions of the rollers define a conveying plane on which items, such as boxes, pallets and the like, may be conveyed. A typical endless belt conveyor also includes a pair of parallel side rails joined by several transverse connector bars to form a rigid frame. But, instead of the relevant items being moved forward by the rotating rollers, the items are moved by an endless belt, driven by a motorised drive roller. Multiple drive rollers can of course be used, which is common in long conveyor assemblies or assemblies which incorporate changes in direction. The motorised drive rollers) may be located at any desired locations along the conveyor assembly (e.g. near the centre of the conveyor assembly, lhe head of the assembly or at the tail of the assembly).

Typically, conveyor systems are purpose designed and built. That is, conveyor systems are generally designed for a particular application in a specified location and are built and installed accordingly. However, it is becoming increasingly important that conveyor systems are able to be modified or changed to accommodate changes in design or function of a particular location or production system. A conveyor system which is able to be readily modified enables manufactures, operators and distributors to be flexible and responsive to changes in demand or market requirements.

However, it is generally difficult and expensive to modify or change conveyor systems after they have been installed. Also, when such a conveyor system is modified or changed, this is generally a time consuming exercise during which the conveyor system is unable to operate, resulting in significant 'down time" and consequent loss in productivity of the relevant business. Another common problem Lu known conveyor systems is the problem of accumulation and backliπe pressure. When items are conveyed on a conveyor system, it is common for them to back up or accumulate on the conveyor. When this happens, the items tend to push against each other causing backline pressure to increase. Such backliπe pressure is undesirable and can cause damage to the items and to the conveyor system itself.

In order to address some of the above problems in standard conveyor systems, a number of different modular conveyor systems have been developed. These modular systems generally enable a conveyor assembly to be modified or changed with less difficulty or expense as the modification or change may be achieved by rearranging the positions of appropriate conveyor modules of the assembly. Some examples of known modular conveyor assemblies are provided below.

US 5,797,481 relates to a ' modular conveyor system' in which particular 'modular conveyor units' are selectively affixed to a ^* horizontally-elongated spine' . The actual length of this spine, and supporting rails, can be varied as desired but, in order to do this, the spine and rails need to be cut to the desired length. This, of course, is a relatively awkward and time-consuming operation.

US 5,188,210 also relates to a ' modular conveyor' system. This system includes a number of conveyor modules which are adapted to be located in a scries thereby forming a continuous conveyor system. Each conveyor module includes a basic frame to which conveyor belts are mounted. In this system, each conveyor module may be run by a drive roller attached to a drive motor. In one embodiment of the invention described, each pair of adjoining conveyor modules is linked by an endless drive chain which extends between lhe drive rollers of these adjoining modules (see Figure 5).

In an alternative embodiment, a number of conveyor modules may be run by a single drive motor. In this embodiment, separate endless, drive chains may extend between the drive rollers of each pair of adjoining conveyor modules (see Figure 6). Alternatively, a single endless drive chain can engage lhe drive roller of each module and be used to drive the modules (see Fig T).

In all of these arrangements described in US 5,188,210, the drive chain (or chains) extend between and engage the drive rollers of adjoining conveyor modules, so that, when the motor is engaged, all of the modules convey items in the same direction, at the same time and at the same pace. US 6,009,994 discloses a 'modular conveyor system" which includes a plurality of non-contiguous, freestanding pedestals, arranged in two parallel rows. Each pedestal includes a drive wheel and a drive belt extends between the drive wheels of adjoining pedestals (see Figure 1 ). The system disclosed in this patent shows a single motor effectively driving the drive wheel of the first pedestal. This causes movement of the drive belt which extends between the drive wheels of the first and second pedestals. The drive wheels of other pedestals in the system, which are also connected in a similar way by drive bells, are consequently also caused to rotate.

Although the above modular systems may be less awkward and expensive to modify or change, in a particular setting? than custom built conveyor systems, they still suffer certain deficiencies. For instance, all of the conveyor modules disclosed in the above prior art are designed to be operated together and convey items in the same direction, at the same time, and at the same pace. Such systems are not readily able to provide for accumulation of items at an end (or other position) of the conveyor system without significant backline pressure.

The present invention is directed towards ameliorating some of the above identified problems in known conveyor systems. In particular, the present invention is directed to a modular conveyor system which may enable accumulation of items without significant backline pressure.. It is further desired that the modular conveyor system may be adapted to have specific conveyor elements, such as a transfer table or a rotary table, attached thereto without having to rearrange the conveyor units of the modular conveyor system.

Summary of the Invention

According to a first aspect of this invention, there is provided a modular conveyor syslem including: a head conveyor unit having a front drive roller located adjacent a forward end of said head conveyor unit; a rear conveyor unit having a rear idler roller located adjacent a rearward end of said rear conveyor unit; a first common axle, located substantially intermediate said forward end and said rearward end, having located thereon both a front idler roller in substantial alignment . with the front drive roller and a rear drive roller in substantial alignment with the rear idler roller; a primary endless drive chain operatively extending about the front drive roller and the front idler roller; and a secondary endless drive chain operatively extending about the rear drive roller and the rear idler roller.

Typically, in this embodiment, the front drive roller is driven by a first molor and the rear drive roller is driven by a second motor. Preferably, the front drive roller is located on a front axle. Similarly, the rear idler roller is preferably located on a rear axle.

It is further preferred that the front axle also includes a second front drive roller, axialJy spaced from the front drive roller, and that the first common axle also includes a second front idler roller, axially spaced from the front idler roller, in substantial alignment with the second front drive roller. Similarly, it is preferred that the rear axle also includes a second rear idler roller, axially spaced from the rear idler roller, and that the first common axle further includes a second rear drive roller, axialJy spaced from the rear drive roller, in substantial alignment with the second rear idler roller of the rear axle. In this embodiment, a second primary endless drive chain operatively extends about the second front drive roller and the second front idler roller. Similarly, a second secondary endless drive chain operatively extends about die second rear drive roller and the second rear idler roller.

In the above embodiment, it is particularly preferred that the front idler roller is located adjacent to the rear drive roller on the first common axle. Similarly, it is preferred that the second front idler roller is located adjacent to the second rear drive roller on said first common axle.

In a second aspect of this invention there is provided a modular conveyor system including: a head conveyor unit having a front drive roller located adjacent a forward end of said head conveyor unit; a rear conveyor unit having a rear idler roller located adjacent a rearward end of said rear conveyor unit; and at least one intermediate conveyor unit, located intermediate the head conveyor unit and the rear conveyor unit; wherein, located adjacent to the junction of adjoining conveyor units, lhere is a common axle having located thereon both an intermediate idler roller in substantial alignment with a drive roller of an adjoining conveyor unit, in a firsl direction, and an intermediate drive roller in substantial alignment with an idler roller of an adjoining conveyor unit, in a direction opposed to the first direelion, and wherein an endless drive chain operatively extends about the aligned drive roller and idler roller of adjoining conveyor units. Preferably, each said drive roller is adapted to be driven by a motor dedicated to said drive roller. Each dedicated motor is adapted so that it may, selectively, be run simultaneously with, or independently of, the other dedicated motors of other conveyor units in the system.

Preferably, the front drive roller is located on a front axle of the head conveyor unit. Similarly, the rear idler roller is preferably located on a rear axle of the rear conveyor unit.

It is further preferred that, on each common axle, the intermediate idler roller is located adjacent to the intermediate drive roller.

In a particularly preferred embodiment:

- the front axle includes a second front drive roller, axially spaced from the front drive roller;

- each common axJe includes a second intermediate idler roller in substantial alignment with a drive roller of an adjoining conveyor unit, in a first direction, and a second intermediate drive roller ill substantial alignment with an idler roller of an adjoining conveyor unit, in a direction opposed to the first direction, said second intermediate idler roller and second intermediate drive roller being axially spaced from the idler roller and the drive roller of said common axle; and

- the rear axle includes a second rear idler roller axially spaced from the rear idler roller. In this embodiment, a second endless drive chain operatively extends about the aligned second drive roller and the second idler roller of adjoining conveyor units.

Generally, each conveyor unit will further include chain support means for supporting each endless drive chain in the unit. The chain support means may be a track, a channel or an elongaled support strip which underlies at least a portion of said endless chain. Typically, as the loads being conveyed (e.g. pallets) will be seated on the endless chains, it is preferred thai each conveyor unit further includes load support means. These load support means may be one or more transverse support bars which extend between opposed sides of each unit. In this embodiment, (he chain support means is preferably located on top of the transverse support bars.

Typically, trie sides of each conveyor unit will be formed of a pair of opposed parallel rails. In this embodiment, the chain support means may comprise a flange extending inwardly from each parallel rail. The transverse support bars would then typically extend between these rails and be positioned immediately beneath the flange of each parallel rail. In a particularly preferred embodiment of the present invention, the chain support means and the transverse support bars are formed on a frame element, said frame element being removeably attachable to the parallel side rails. Obviously, this frame element is thereby able to be positioned between the opposed side rails. Typically_; each frame element includes opposed side portions adapted to be connected to the parallel side rails and chain support means substantially adjacent to each side portion, wherein the transverse support bars extend between the side portions.

Fn a further particularly preferred embodiment of this invention, and in order to facilitate the modular nature of the conveyor system, there are preferably a number of different frame elements Typically, these different frame elements are:

Module A (lower) - where each chain support means is adapted Io support a lower tracking of the endless chain and is located adjacent to one of the side portions;

Module A (upper) - where each chain support means is adapted to support an upper tracking of the endless chain and is located adjacent to one of the side portions; Module B (lower) - where each chain support means is adapted to support a lower tracking of the endless chain and is located a short distance from, one of the side portions, said short distance being at least equal to the width of said chain; and

Module B (upper) - where each chain support means is adapted to support an upper tracking of the endless chain and is located a short distance from one of the side portions, said short distance being at least equal to the width of said chain.

Preferably, when in position between the parallel side rails, a Module A (lower) frame clement is positioned below (preferably directly beneath) a Module A (upper) frame element. Similarly, a Module B (lower) frame element is typically positioned below (preferably directly beneath) a Module B (upper) frame element.

As will be apparent from the above, the main difference between the Module A and Module B frame elements is the location of the chain support means.. In the Module B frame element, each of the chain support means is located slightly inwardly of the corresponding chain support means of the Module A frame element The reason for this is that, when the above described modular conveyor system includes one or more common axles and, each common axle having an idler roller and an adjoining drive roller, the endless chains associated with each roller will be spaced apart by about the width of the chain (or the width of a roller).

This arrangement enables a modular conveyor system to be constructed having a pair of Module A frame elements (i.e. Module A (lower) and Module Λ (upper)) positioned alongside Module B frame elements (i.e. Module B (lower) and Module B (upper)), and a common axle located between these pairs of frame elements, without the relevant adjoining endless chains interfering with one another. Accordingly, this modular system enables a multitude of different arrangements to be constructed.

For instance, the conveyor system couJd be constructed having a series of Module A frame elements alongside each other. Similarly, the conveyor system could have a series of Module B frame element alongside each other. Alternatively, there could be a combination of Module A and Module B frame elements put together in a number of different desired orientations. As will be appreciated, when a conveyor system comprises a series of frame elements of the same module type (i.e. Module A or Module B), the conveyor system will be adapted to move items forward or backward in a continuous direction. When, however, the conveyor system comprises a combination of Module A and Module B frame elements, the syslem will be better adapted to selectively move items on one module or one type of module (e.g. Module A frame element(s)) whilst leaving items on the other module or other type of module (e.g. Module B frame element(s)) stationary.

As will be appreciated, the abovementioned conveyor units may be of any desired size, shape and/or dimension. Typically, but not necessarily, the conveyor units in any one conveyor system arc generally of the same size, shape and dimension. In one preferred embodiment, each conveyor unit has a length of about 1.5 metres. In this embodiment, conveyor systems can be formed having lengths in any multiple of 1.5m (e.g. 3m, 4.5m, 6m, 7.5m, 9m etc.). Each conveyor unit may, however, be of any appropriate desired size and the conveyor system may be constructed of any combination of these.

Accordingly, the opposed parallel sides of the above conveyor system may be formed of a series of parallel side rails of suitable lengths (e.g. 1.5m, 3.0m. 4.5m). These parallel side rails may be joined together, in any desired orientation, so as to construct a conveyor system of desired length. As noted above, the frame elements may be positioned, between these parallel side rails, at suitable locations along the conveyor system. Similarly, the drive rollers and the idle rollers can be positioned at desired locations along the conveyor system.

According to a further aspect of this invention, there is provided an internal module, adapted to be affixed to a conveyor unit of a conveyor system according to the first or second aspect of this invention. Preferably, this internal module is selected from a transfer table unit and a rotary table unit. Preferably, the internal module includes affixing means for affixing the module to a conveyor unit The affixing means may include side segments, on opposed sides of the module, adapted to be bolted to the side rails of the conveyor unit

In a particularly preferred embodiment, the internal module includes an upper table portion and lifting means adapted to selectively move the upper table portion from a recessed position to an elevated position at which the upper table portion may receive or transfer a load being conveyed. The internal module may include a base portion. In this embodiment, the lifting means may be located intermediate the base portion and the upper table portion. The lifting means may, for example, be a pneumalic lifting device. Preferably, of course, the lifting means is also adapted to lower the upper table portion back into the recessed position when it is not required.

Brief Description of Drawings

The invention will now be further explained and illustrated by reference to the accompanying drawings in which:

Figure 1 is a perspective view of a single conveyor unit fσr a modular conveyor system according tα the first aspect of the present invention. Figure 2 is a perspective view of a modular conveyor system, having 2 conveyor units, according to a preferred embodiment of the first aspect of the present invention.

Figure 3 is a perspective view of a modular conveyor system, having 3 conveyor units, according to a preferred embodiment of the second aspect of trie present invention.

Figure 4 is a perspective view of an alternative modular conveyor system, having 3 conveyor units, according to another preferred embodiment of the second aspect of the present invention.

Figure 5 is a perspective view of a further alternative modular conveyor system, having 3 conveyor units.

Figure 6 is a perspective view of a transfer table, according to an embodiment of a further aspect of the present invention.

Figure 7 is a perspective view of a modular conveyor system (having 3 conveyor units) and a transfer table (of Figure 6), immediately prior to installation of the said transfer table, according to a prefciTcd embodiment of this invention.

Figure 8 is a perspective view of a portion a modular conveyor system (having 3 conveyor units) and a transfer table instaJlcd therein, according to a preferred embodiment of this invention, with a portion of an adjoining, transversely extending, conveyor system having a loaded paLIet thereon.

Figure 9 is a perspective view of a 1.5m side rail for use iu an embodiment of this invention. Figure 10 is a perspective view of a 3.0m side rail for use iu an embodiment of this invention.

Figure 1 1 is a perspective view of a 4.5m side rail for use in an embodiment of this invention.

Figure 12 is a perspective view of a frame element, containing a lower, outer chain guide, for use in an embodiment of this invention.

Figure 13 is a perspective view of a frame element, containing an upper, outer chain guide, for use in an embodiment of this invention.

Figure 14 is a perspective view of a frame element, containing a lower, inner chain guide, for use in an embodiment of this invention. Figure 15 is a perspective view of a frame element, containing an upper, inner chain guide, for use in an embodiment of this invention.

Figure 16 is a perspective view of a transfer module element, containing a lower, outer chain guide, for use in an embodiment of this invention.

Figure 17 is a perspective view of a transfer module element, containing a lower, inner chain guide, for use in an embodiment of this invention.

Description of Preferred Embodiments

The above figures illustrate preferred embodiments of the present invention. A single conveyor unit, for use in the modular conveyor system of tin's invention, is shown in Figure 1. As can be seen, the modular conveyor unit I has a front end 2 and a rear end 3 and is formed from various elements built onto a frame 4. The frame 4 includes a pair of opposed parallel side rails 5, a pair of upper transverse cross beams 6a and a pair of lower transverse cross beams 6b. These cross beams 6a, 6b extend horizontally between the side rails 5. The cross beams 6a_> 6b are typically affixed to the side rails 5 by bolting the ends of the cross beams to the side rails.

The conveyor unit 1 also includes a front axle 7 located near the front end 2 of the unil and a rear axle 9 located near the rear end 3 of said unit. The front axle 7 includes two axially spaced drive rollers 8 (although only one of these is visible in Figure 1 ). The drive rollers 8 are located near opposite ends of the front axle 7 and adjacent inside surfaces of the parallel side rails 5. The rear axle 9 includes two axially spaced idler rollers 10 (although only one of these is clearly visible )π Figure 1). The idler rollers 10 are located near opposite ends of the rear axle 9 and adjacent inside surfaces of the parallel side rails 5. Accordingly, the two drive rollers 8 and the two corresponding idler rollers 10 arc in substantial alignment. An endless drive chain 1 1 opcratively extends about the drive roller 8 and the idler roller 10.

The front axle 7, and the attached drive rollers 8, are in operational engagement with a motor 12. The motor 12 is conveniently affixed to one of the side rails 5, preferably adjacent to an outer surface of said side rail. In the embodiment shown, the motor 12 is located adjacent an end of the front axle 7. The motor 12 is then able directly to drive the front axle 7.

I'he frame 4 also includes an upper chain support track 13 and a lower chain support track 14. Both the upper and the lower chain support tracks 13, 14 are located adjacent to the inside face of the side rails 5. These tracks are designed so as to support and guide the endless drive chain 1 1 as it travels between the drive roller 8 and the idler roller 10. Accordingly, the chain support tracks 13, 14 are in alignment with said drive roller 8 and the idler roller 10. In the embodiment shown in Figure 1, the chain support tracks 13, 14 are located upon the transverse cross beams. Each lower chain support track 14 is located upon the lower transverse cross beams 6b. Each upper chain support track 13 is located upon the upper transverse cross beams 6a. Another reason for locating the upper chain support truck 13 upon the upper transverse cross beams 6a is that, when in use, loads (such as loaded pallets) are carried on top of the endless drive chain 11 and the chain needs support for this This support is provided by the upper chain support track 13 and the upper transverse cross beams 6a.

The frame 4 also includes opposed guide rails 15 on the parallel side rails 5. These guide rails 15 serve to guide the loads being coDveyed along the coπveyoi system. The guide rails 15 also serve so as to keep the loads (e.g. loaded pallets) in alignment and Io prevent them from slipping sideways off the conveyor system.

The frame 4 also includes legs 16 which underlie the parallel side rails 5. These legs 16 may be of any desired height depending on the required height of the conveyor system.

Figure 2 shows a modular conveyor system consisting essentially of two conveyor units. Most of the features of this conveyor system are similar to the features described above in relation to the single conveyor unit shown in Figure I . However, when two or more conveyor units are combined, certain adaptations need to be made and these arc quite clearly shown in Figure 2. For instance, Figure 2 shows a first conveyor unit 1 A joined to a second conveyor unit 1 B. Adjacent to where the two conveyor units meet, there is a common axle 20. The common axle 20 lias two axial Iy spaced idler rollers (which are not clearly visible in Figure 2) which are in alignment with the drive roller 8A of the first conveyor unit IA. The common axle 20 also has two axially spaced drive rollers 8B. These drive rollers 8B are located adjacent to the above-mentioned idler rollers on the common axle 20. The second conveyor unit 1 B also includes a rear axle 9B located near a rear end thereof. This rear axle 9B includes two axially spaced idler rollers 1 OB which are in alignment with the drive rollers 8B of the common axle 20.

The first conveyor un it 1 A includes two primary endle-ss drive chains 1 1 A, each of which operatively extends about a drive roller 8A (on the front axle 7) and an idler roller (on (he common axle 20). Similarly, the second conveyor unit I B includes two secondary endless drive chains 1 1 B, each of which operatively extends about a drive roller 8B (on the common axle 20) and an idler roller 1 OB (on the rear axle 9B).

In the embodiment of the invention shown in Figure 2, each conveyor unit IA, IB has its own motor 12. The motor 12 on the first conveyor unit I A drives the front axle 7 and the front drive rollers 8A. The motor 12 on the second conveyor unit IB drives the common axle 20 and the drive rollers 8 B (on said axle).

The modular conveyor system shown in Figure 2 may he run as a uniform conveyor in which case both of the motors 12 run together. In this way, the drive rollers 8A, 8B arc driven together causing the endless drive chains 1 IA. 1 1 B to run simultaneously, resulting in a conveyor system in which a load may be moved along the entire length of the system.

Alternatively, the motors 12 may be run individually, meaning that one motor 12 is run whilst another is not run. This may be desirable, for instance, when a load is just to be moved along one of the conveyor units.

Figure 3 shows a conveyor system having series of three conveyor units IA, I B and 1C. This system is, in effect, an extension of the conveyor system shown in Figure 2. As can be seen, this conveyor system includes a front axle 7 adjacent a front end of the first conveyor unit IA and a rear axle 9C adjacent a rear end of the third conveyor unit 1C. Adjacent to where the first and second conveyor units IA, I B meet, there is a common axle 20. Similarly, there is another common axle 20 adjacent to where the second and third conveyor units IB, 1C meet. Each common axle 20 has two axially spaced idler rollers (which are not clearly visible in Figure 3) which are in alignment with corresponding drive roJlcrs of an adjoining conveyor unit (in a first direction), and two axially spaced drive rollers (which also are not clearly visible in Figure 3) which are in alignment with corresponding idler rollers of an adjoining conveyor unit (in a direction opposite to the first direction.)

Λs can be seen in Figure 3. the first conveyor unit 1Λ includes two primary endless drive chains 1 IA, each of which operatively extends about a drive roller 8 A (on the front axle 7) and an idler roller (on the common axle 20B). Similarly, the second conveyor unit 1 B includes two secondary endless drive chains 1 1 B, each of which operatively extends about a drive roller 8B (on the common axle 20B) and an idler roller 1 OB (on the common axle 20C). In a similar tashion, the third conveyor unit 1C includes two tertiary endless drive chains 1 1C, each of which operatively extends about a drive roller 8C (not clearly visible in Figure 3) (on the common axle 20C) and an idler roller 1 OC (on the rear axle <>C).

In the embodiment of the invention shown in Figure 3, each conveyor unit IA, I B, 1 C has its own motor 12. The motor 12 on the first conveyor unit IA drives the front axJe 7 and lhe front drive rollers 8A. The motor 12 on the second conveyor unit IB drives the common axle 20B and the drive rollers 8B (on said common axle). The motor 12 on the third conveyor unit 1C drives the common axle 20C and the drive rollers 8C (not clearly visible in Figure 3) (on said common axle 20C).

The modular conveyor system shown in Figure 3 may be ran as a uniform conveyor in which case all of the motors 12 nin together. In this way, the drive rollers 8A, 8B, 8C are driven together causing the endless drive chains 1 1 A, 1 IB, 1 1C to run simultaneously, resulting in a conveyor system in which a load may be moved along the entire length of the system.

Alternatively, the motors 12 may be run individually or in desired permutations of two on and one off or one on and two off. This may be desirable, for instance, when accumulation of a load is required. For example, in the situation where a load (e.g. a pallet) has been moved up to, and is located on, the first conveyor unit IA, the motor 12 which drives front axle 7 (and front drive roller SA) may be switched off. The motors of the adjoining conveyor units 1 B, 1 C may then continue to operate so that another load (e.g. a pallet) is moved up to, and is located on, the second conveyor unit IB. When in this position, the motor 12 which drives common axle 2OB (and drive roller 8B) may be switched off. This enables convenient accumulation of loads on adjoining conveyor units with the further advantage that back-line pressure can be avoided or, at least, substantially reduced. As will be appreciated, in a modular conveyor system having a multitude of such conveyor units, the motors of adjoining conveyor units may (in a similar manner to that described above) be switched off sequentially to enable accumulation of loads on adjoining conveyor \mits. Again, this has tlie advantage of avoiding or substantially reducing back-line pressure in the system.

Figures 4 and 5 show alternative permutations of a conveyor system having three conveyor units. The system of Figure 4 has a front axle 7 (with front drive rollers 8A), driven by a first motor 12, but only one common axle 2OB (with drive rollers 8B), driven by a separate motor 12, adjacent to the join bel ween adjoining conveyor units lA and I B. The system of Figure 5 does not have any common axle. The system is driven by a single motorised front axle 7 (with drive rollers S), connected Lo motor 12.

Figure 6 shows a transfer table 30 for use in a modular conveyor system according to the first and/or second aspects of the present invention. The transfer table 30 includes opposed side portions 31 which are adapted to be attached to the parallel side rails 5 of a conveyor unit of modular conveyor system. Typically, the side portions 31 include holes which align with corresponding holes in the side rails 5, so that bolts can be passed through the aligned holes in order to affix said side portions 31 to the parallel side rails 5.

The particular transfer table 30 shown in Figure 6 also includes a base formation 32 and an upper formation 33. The base formation 32 may include two cross bars 32A. These cross bars 32A are connected to the side portions 31 by means of connector bars 34. As will be appreciated, in the embodiment of the transfer table 30 shown, the cross bars 32A of the base formation 32 may (when positioned in a conveyor unit) take the place of the transverse cross beams 10 of the conveyor unit in which the transfer table 30 is located. In this case, two chain support tracks 13 A are positioned on the connector bars 34. These chain support tracks 13A run parallel and adjacent to the side rails 5 of the conveyor unit to which said transfer table 30 is designed to be attached and they are adapted to receive the endless drive chains I I, 1 1 A, 1 I B etc of said conveyor unit.

The upper formation 33 includes two opposed transverse endless chains 40 which extend substantially across the width of the transfer table 30 in a direction substantially normal to the direction in which the endless drive chains 1 1 , 11 A, 1 1 B etc of the above-described conveyor units run. In the embodiment shown, the upper formation 33 also includes a motorised central axle 41 which, when activated, is adapted to drive the transverse endless drive chains 40. The transfer table 30 also includes lifting means (not shown) for lifting the upper formation 33 relative to the base formation 32. Typically, the lifting means is a pneumatic lifting device located substantially intermediate the base formation 32 and the upper formation 33 of the transfer table 30. This lifting means is adapted to, selectively, raise and lower the upper formation 33 of the transfer S table 30. For instance, when the transtcr table is not required, the upper formation 33 is maintained in a recessed position nearer to the base formation 32. In this recessed position, the transverse endless chains 40 are at a height which is lower than the height of the endless drive chains 1 1, ! 1 A, 11 B etc (which pass along the chain support tracks 13A) of the above-described conveyor units. When the upper formation 33 is in an elevated position, the transverse endless chains 40 are at a 0 height greater than that of the drive chains of the relevant conveyor unit. Thus, when the transverse endless chains 40 are activated, any load sitting on the transverse endless chains 40 will be caused to move in the transverse direction of these chains.

Figure 7 shows a transfer table 30 about to be positioned into a conveyor system as described above. As shown in Figure 7, the transfer table 30 is generally positioned within, and intermediate the ends of, a single conveyor unit .

Figure 8 shows a portion of a conveyor system as described above incorporating a traπsfcr table 30 therein. Alongside the transfer table is a separate conveyor system 40 joining the first-mentioned conveyor system at right angles. The transfer table is able to receive a load 50, travelling in a first direction, from the separate conveyor system 40 and then pass it along the first mentioned conveyor system, in a second direction at right angles to the first direction. Or, in reverse, the transfer table 30 can transfer the load 50 from the first mentioned conveyor system to the separate conveyor system 40 in a similar manner.

The above described modular conveyor system may be constructed from a number of standard elements. These standard elements may include side rails of standard lengths and frame elements, such as the Module A (lower), Module A (upper), Module B (lower) and Module B (upper) frame elements described above. Examples of such standard elements are illustrated in Figures 9 to 17.

Figures 9 to 1 1 show side rails. 5Λ, 5B and 5C, of three different lengths, such as 1 .5m, 3.0m and 4.5m. fcach side rail includes axle holes 50, frame element holes 51 , motor securing holes 52 and top holes 53 for securing guide rails 15. The axles (on which are located the rollers) are secured to the axle holes 50, in their desired positions on the parallel side rails 5. The frame elements (discussed below) are secured to the parallel side rails by virtue of the frame element holes 51. The motor 12 which drives a drive roller is affixed to the adjoining parallel side rails by virtue of the motor securing holes 52.

Figure 12 shows a frame element 6OA which corresponds to a Module A (lower) frame element. This name element 60A includes a pair of lower chain tracks 14A, each of which is located adjacent to a lower side portion 63. Each lower chain track 14Λ is seated upon a pair of lower transverse cross beams 6b which extend between the two lower side portions 63. A nut and bolt arrangement 66 is used to secure the frame element 6OA to the parallel side rails 5 of the conveyor system.

Figure 13 shows a frame element 61 A which corresponds to a Module A (upper) frame element. The basic structure of frame element 61 A is similar to that of frame element 6OA. It includes a pair of upper chain tracks 13 A, each of which is located adjacent lo an upper side portion 64. Each upper chain track 13Λ is seated upon a pair of upper transverse cross beams 6a which extend between the two upper side portions 64. A nut and boh arrangement 66 is used to secure the frame element 61 A to the parallel side rails 5 of the conveyor system.

Figure 14 shows a frame element 6OB which corresponds to a Module B (lower) frame clement. Again, the basic structure of frame element 6OB is similar to that of frame element 6OA. This frame element 60B includes a pair of lower chain tracks 14B, each of which is located a short distance inwards of the lower side portion 63. Each lower chain track I4B is seated upon a pair of lower transverse cross beams 6b which extend between the two lower side portions 63. A nut and bolt arrangement 66 is again used to secure the frame element 6OB to the parallel side rails 5 of the conveyor system.

Figure 15 shows a frame element 61 B which corresponds to a Module B (upper) frame element. Again, the basic structure of frame element 61 B is similar to that described above. It includes a ' pair of upper chain tracks I3B, each of which is located a short distance inwards of the upper side portion 64. Rach upper chain track 13 B is seated upon a pair of upper transverse cross beams 6a which extend between the two upper side portions 64. A nut and bolt arrangement 66 is used to secure the frame element 61 A to the parallel side rails 5 of the conveyor system.

Figures 12 to 15 may be read with Figures 1 to 5 which show the frame elements in position in the conveyor system. For instance, Figure 2 shows a conveyor system having a pair of Module A frame elements (e.g. Module A (lower) and Module A (upper) alongside a pair of Module B frame elements (e.g. Module B (lower) and Module B (upper). As can be seen, the adjoining continuous chains are slightly offset owing to the fact that they are connected to adjoining rollers on the common axle. This illustrates why the chain tracks of Module B frame elements are located further inwards, from the side portions, than the chain tracks of Module A frame elements.

Figures 16 and 17 show frame elements 65A and 65B which have transverse cross beams (6c and 6d, respectively) which are stepped. This is achieved by a step section 67. These frame elements are designed to support a transfer table or a rotary table.

As will be appreciated, a rotary table (for a conveyor system) may be installed onto a conveyor unit in a similar manner to thai described above in relation to said transfer table.

The word 'comprising', and other forms of this word (e.g. 'comprises'), as used in lhis specification, is not intended to (and does not) Hm it the invention defined or described so as to exclude any variants or additions.

The present invention has been described by reference to certain preferred embodiments.

Nevertheless, as will be appreciated by skilled persons in the relevant art, the invention is not so limited and it may include modifications and adaptations which are within the meaning and scope of the invention described and/or defined herein.

Claims

The claims defining this invention are as follows:

5 1. A modular conveyor system including: a head conveyor unit having a front drive roller located adjacent a forward end of said head conveyor unit; a rear conveyor unit having a rear idler roller located adjacent a rearward end of said rear conveyor unit; 10 - a first common axle, located substantially intermediate said forward end and said rearward end, having located thereon both a front idler roller in substantial alignment with the front drive roller and a rear drive roller in substantial alignment with the rear idler roller; a primary endless drive chain operatively extending about the front drive roller and the I 5 front idler roller; and a secondary endless drive chain operatively extending about the rear drive roller and the rear idler roller. 2. A modular conveyor system according to claim 1 , wherein the front drive roller is driven by a first motor and the rear drive roller is driven by a second motor. 0 3 A modular conveyor system accord ing to claim 1 or claim 2 wherein the front drive roller is located on a front axle and the rear idler roller is preferably located on a rear axle.

4. A modular conveyor system according to any one of the preceding claims, wherein the front axle also includes a second front drive roller, axially spaced from the front drive 5 roller, and the first common axle also includes a second front idler roller, axially spaced from the front idler roller, in substantial alignment with the second front drive roller.

5. A modular conveyor system according to any one of the preceding claims, wherein the rear axle also includes a second rear idler roller, axially spaced from the rear idler0 roller, and that the first common axle further includes a second rear drive roller, axially spaced from the rear drive roller, in substantial alignment with the second rear idler roller of the rear axle.

6. A modular conveyor system according to claim 4, further includ ing a second primary endless drive chain operatively extending about the second front drive roller and the5 second front idler roller.

7. A modular conveyor system according to claim 5, further including a second secondary endless drive chain operatively extending about the second rear drive roller and the second real' idler roller.

8. A modular conveyor system according to any one of the preceding claims wherein the 5 front idler roller is located adjacent to the rear drive roller on the First common axle.

9. Λ modular conveyor system according to any one of claims 4 to 7 wherein the second front idler roller is located adjacent to the second rear drive roller on the first common axle.

10. A modular conveyoT system including:

I O o a head conveyor unit having a front drive roller located adjacent a forward end of said conveyor unit; o a rear conveyor unit having a rear idler roller located adjacent a rearward end of said rear conveyor unit; and o at least one intermediate conveyor unit located intermediate the head conveyor 1 5 unit and the rear conveyor unit; wherein, located adjacent to the junction of adjoining conveyor unils, there is a common axle having located thereon both an intermediate idler roller in substantial alignment with a drive roller of an adjoining conveyor unit, in a first direction, and an intermediate drive roller in substantial alignment with an idler roller of an 0 adjoining conveyor unit, in a direction opposed to the first direction, and wherein an endless drive chain operatively extends about the aligned drive roller and idler roller of adjoining conveyor units.

1 1. A modular conveyor system according to claim 1 0, wherein each said drive roller is adapted to be driven by a motor dedicated to said drive roller. 5 12. A modular conveyor system according to claim 10 or claim 1 1. wherein each dedicated motor is adapted so thai, it may, selectively, be run simultaneously with, or independently of_; the other dedicated motors of other conveyor units in the system.

13. A modular conveyor system according to any one of claims 10 to 12, wherein the Front drive roller is located on a front axle of the head conveyor unit and the rear idler roller0 is located on a rear axle of the rear conveyor unit.

1 4. A modular conveyor system according to any of claims 10 to 13, wherein, on each common axle, the intennediate idler roller is located adjacent to the intermediate drive roller.

15. A modular conveyor system according to any one of claims 10 to 14, wherein: 5 o the front axle includes a second front drive roller, axially spaced from the front drive roller; o each common axle includes a second intermediate idler roller in substantial alignment with a drive roller of an adjoining conveyor unit, in a first direction, and a second intermediate drive roller in substantial alignment with an idler roller of an adjoining conveyor unit, m a direction opposed to the first direction, said second intermediate idler roller and second intermediate drive roller being axially spaced from the idler roller and the drive roller of said common axle; and; o the rear axle includes a second rear idler roller axially spaced from the rear idler roller; wherein a second endless drive chain operatively extends about the aligned secondary drive roller and the secondary idler rollei of adjoining conveyor unils. 16. A modular conveyor system according to any one of claims 1 to 15, wherein each conveyor unit further includes chain support means for supporting each endless drive chain in the unit. 1 7. Λ modular conveyor system according to claim 16, wherein the chain support means is a track, a channel or an elongated support strip which underlies at least a portion of said endless chain. 18. A modular conveyor system according to any one of claims 1 to 17, wherein each conveyor unit further includes load support means. 19. A modular conveyor system according to claim 18, wherein the load support means comprises one or more transverse support bars which extend between opposed sides of each conveyor unit. 20. A modular conveyor system according to claim 19, wherein the chain support means is located on top of the transverse support bars. 21. Λ modular conveyor system according to claim 19 or claim 20, wherein the opposed sides of each conveyor unit comprise a pair ofopposed parallel rails.

22. Λ modular conveyor system according to claim 21 wherein the chain support means and the transverse support bars are formed on a frame element, said frame element being removeably attachable to the opposed side rails. 23. A modular conveyor system according to claim 22 wherein the frame element includes opposed side portions adapted to be connected to the opposed side rails and chain support means substantially adjacent to each side portion, wherein the transverse support bars extend between the side portions.

24. A modular conveyor system according to claim 23 wherein each chain support means is adapted to support the endless chain in a lower tracking of the chain and is located adjacent to one of the side portions.

25. A modular conveyor system according to claim 23 wherein each chain support means is adapted to support the endless chain in an upper tracking of the chain and is located adjacent to one of the side portions.

26. A modular conveyor system according to claim 23 wherein each chain support means is adapted to support the endless chain in a lower tracking of the chain and is located a short distance from one of the side portions, said short distance being at least equal to the width of said endless chain.

27. A modular conveyor system according to claim 23 wherein each chain support means is adapted to support the endless chain in an upper tracking ofthe chain and is located a short distance from one ofthe side portions, said short distance being at least equal to the width of said endless chain.

28. Λ modular conveyor system according to claim 24 or claim 25, wherein the frame element of claim 24 is positioned below the frame element of claim 25.

29 A modular conveyor system according to claim 26 or claim 27, wherein the frame element of claim 26 is positioned below the frame element of claim 27.

30. A modular conveyor system according to claims 28 and 29 wherein a pair of frame elements of claims 24 and 25 is located substantially adjacent to a pair of frame elements of claims 26 and 27.

31. A modular conveyor system according to claim 28 wherein a pair of frame elements of claims 24 and 25 is located substantially adjacent to at least one other pair of frame elements of claims 24 and 25.

32. A modular conveyor systern according to claim 29 wherein a pair of frame elements of claims 26 and 27 is located substantially adjacent to at least one other pair of frame elements of claims 26 and 27. 33. An internal module, for use in a conveyor unit of a conveyor system according to any of claims 1 to 32, said internal module including affixing means for affixing the module to a conveyor iin it.

34. An internal module according to claim 33, wherein said internal module is selected from a transfer table unit and a rotary table unit. 35. An internal module according to claim 34, wherein the internal module includes an upper table portion and lifting means adapted to selectively move the upper table portion from a recessed position Io an elevated position at which the upper (able portion may receive a load being conveyed.