GB2036681A

GB2036681A - Nip conveyor for loading or unloading a ship's hold

Info

Publication number: GB2036681A
Application number: GB7938634A
Authority: GB
Original assignee: GEC Mechanical Handling Ltd; GEC Elliott Mechanical Handling Ltd
Current assignee: Alstom Automation International Ltd
Priority date: 1978-12-05
Filing date: 1979-11-07
Publication date: 1980-07-02
Also published as: GB2036681B

Abstract

Cargo handling equipment, more especially for unloading separate items, such as bags or sacks of cement or cereals, or loose particulate material, from, or loading such items or material into, the holds of ships comprises an elongate elevator unit whose lower end can be introduced into a ship's hold with the upper end projecting upwards therefrom, characterised in that the elevator comprises a pair of endless bands (14, 15) with adjacent runs arranged to be driven in the same direction, one of the adjacent runs being biased towards the other by a plurality of movable rollers (19) spaced along the unit so that with the bands driven in the appropriate direction items or material introduced between the adjacent runs at the bottom or top of the unit, are carried upwards or downwards respectively to be discharged at the top or bottom as the case may be. The rollers 19 are preferably mounted on pivotted arms 20 and are biassed by gravity towards the band 15, backing rollers 22 being provided bearing on the other band 14. <IMAGE>

Description

SPECIFICATION Cargo handling equipment This invention relates to cargo handling equipment, more especially for unloading separate items, such as bags or sacks of cement or cereals, from or loading them into the holds of ships, but can also have application to the loading and unloading of loose particulate material.

According to the invention in its broadest aspect cargo handling eqiupment for loading or unloading separate items or loose particulate material into or from the holds of ships comprises a support structure, and an elongate elevator unit capable of being raised and lowered with respect to the support structure so that an end of the unit can be introduced into the hold of a ship with the opposite end projecting upwards thereform, and the unit incorporating a pair of opposed endless belts extending lengthwise along the unit, means for driving the belts so that adjacent runs travel in the same direction, a plurality of rollers spaced along the unit and biased against at least one of the two adjacent runs of the belts so as to urge it towards the other with a pressure such that items or material introduced between the two adjacent runs of the belts at the commencement of the run are carried between them to the opposite end of the run.

By driving the belts in appropriate directions items or material can be carried downwardly into the hold of a ship for loading purposes or carried upwardly therefrom for unloading.

The optimum spacing of the rollers and the force that they exert on the adjacent belt will depend upon the nature of the items or material to be loaded or unloaded.

In the case of equipment used for unloading items or material from the holds of ships the adjacent runs of the belts are arranged to travel in the upward direction, and the rollers are arranged to be biased against the upwardly travelling run of one of the belts so as to urge it towards the upwardly travelling run of the other belt with a pressure such that said items or material introduced between the adjacent runs of the belts at the lower end are carried upwards thereby, and discharged at the upper end.

The items or material can then be carried from the ship, by means of a chute, endless belt, or other form of conveyor to the dockside either for loading directly into wagons or trucks orfortemporary storage.

The endless belts are preferably arranged to be driven at a substantially constant speed, thereby providing a continuously moving elevator capable of raising the cargo from the hold for transfer from the ship to the dockside at a relatively rapid rate.

The invention has particular application to the unloading of bagged cargo, which term is intended to include within its scope materials in bags, sacks and other like containers, and enables the rate at which such bagged cargoes can be unloaded to be increased, and the unloading time to be consequent ly reduced, compared with conventional forms of cargo handling equipment used for this purpose.

In apparatus designed for unloading standard bags of cement the rollers are preferably spaced apart a distance of between 400mm and 500mm, and are arranged to exert a force on the adjacent belt of between 15kg and 50kg.

However the most satisfactory arrangements for any particular application of the invention for use in loading or unloading may readily be found by trial.

The rollers may be supported on pivoted arms which are inclined upward from the pivot axis towards the belt, so that the rollers are urged against the belt under the force of gravity. The pressure of the rollers on the belt can be supplemented or reduced, if desired, by the provision of weights or counterweights on the arms, or by the use of appropriately acting spring means.

In some cases, however, the rollers may be biased towards the belt by hydraulically or pneumatically operated devices. These can be connected to a central hydraulic or pneumatic pressure regulator, which may be adjusted to enable the force exerted by the rollers on the belt to be quickly and easily changed for the handling of different cargoes.

The rollers are preferably arranged to urge the operative runs of the belts against suitably positioned reaction rollers which bear against the rear surface of said other belt.

Preferably in the case of unloading equipment the main drive is applied to a head pulley supporting the upper end of said other belt, which may have projections on its operative surface to assist it to engage and grip items of cargo required to be unloaded.

The said other belt may also terminate at the lower end in a horizontal or near horizontal extension on to which the cargo is arranged to be placed or fed, to be carried by the belt between the upwardly moving parts of the belts.

Where the lower extension of the belt tends to be pulled upwards by the drive imparted by the head pulley, the tail pulley over which the lower end of the said other belt passes may be arranged to be driven at a peripheral speed which is between 2 and 8 per cent faster than that of the respective head pulley.

The head pulley supporting the upper end of said first belt may also be driven, in some cases by means of a constant torque motor for maintaining the operative run of the belt at a substantially constant tension, although this will not usually be necessary.

The support structure is preferably provided with wheels for enabling the equipment to be moved to various locations on the dockside most suitable for carrying out unloading operations. Preferably at least some of the wheels are steerable and at least some are coupled to a suitable power unit to enable the equipment to be driven under its own power.

The wheels may be arranged to be retracted so that the support structure can be lowered on to fixed pads during loading or unloading operations.

One form of cargo handling equipment in accordance with the invention will now be described by way of example with reference to Figures 1 to 4 of the accompanying schematic drawing, in which Figure 1 represents, in diagrammatic form, a side view of the equipment having an elevator shown in its operative position, Figure 2 represents a similar view of the equipment with its elevator in a raised position, Figure 3 represents a side view of the elevator itself, and Figure 4 shows an enlarged plan section of part of the elevator.

Referring first to Figures 1 and 2, the unloader comprises a mobile platform 1 mounted on powered and steerable pneumatic tyred bogies 2, and carrying a support frame 3. The support frame 3 carries a boom 4which is capable of being raised and lowered about a horizontal pivot 5 at one end. The boom 4 pivotably supports at its outer end an elevator 6 which can also be raised and lowered on movement of the boom, and can also be pivoted about a horizontal axis with respect to the boom.The movement of the boom 4 and elevator 6 is effected by winches 7,8 through respective cable and pulley systems 9, 10, and is such that the elevator 6 can be raised to a position, as illustrated in Figure 2, in which its lower end can be introduced into or subsequently removed from the hold of a ship 11 through a hatch-way 12, or lowered into an operative position as shown in Figure 1, in which its extends vertically through the hatch-way with its lower end within the hold. In addition the operative position of the elevator 6 can be altered to cater four changing tidal conditions, the position of the ship in the water and the height of the cargo in the hold which is to be unloaded.

The elevator itself is shown in more detail in Figures 3 and 4, and comprises an elongated rectangular-section framework 13 (shown schematically and only in part) which is pivoted to the boom 4 near to its upper end. The framework carries a pair of conveyor belts 14,15 extending lengthwise along it and supported by pulleys at the top and bottom.

An electric motor M1 drives the upper pulley 16 which carries the belt 14 in the direction indicated by the arrow 18, so that the inner run of the belt moves in an upward direction.

The inner run of the belt 15 is urged towards the belt 14 by a series of spaced rollers 19 carried by pivoted arms 20, these being inclined upwards from the pivots 21 so that the mass of each roller and its supporting arms provides a horizontal force on the belt 15 pressing it into contact with the other belt 14 which is pressed, in turn, against appropriately positioned reaction rollers 22. The inner run of the belt 15 is thus also caused to travel upwards by frictional engagement with the belt 14.

At the lower end the belts terminate in short horizontally extending regions 23 with the belt 14 projecting beyond the belt 15 as shown, its upper run in this position being supported by a slider bed 25. This provides the loading position for the conveyor. Slider beds 25.1 are also provided between the rollers 22 as shown along the vertical run of the belt 14.

Bags or sacks placed on the horizontal extension of the belt 14 are carried between the two belts 14, 15 as shown at B; the rollers acting on the belt 15 cause the bags or sacks, as the case may be to be held frictionally in contact with the belt 14, which causes them to be carried upwards between the belts and so raised from the hold of the ship. The operative surface of the belt 14 may be formed with projections to provide a gripping face to increase its frictional engagement with the bags or sacks being raised. At the'top, the belt 14 after passing over an idling roller 24 extends in a generally horizontal or only slightly inclined direction to the main head pulley 16 this region of the belt also being supported by a slider bed 25.2 which forms the base of a trough having side walls 30.The pulley 17 carrying the upper end of the other belt 15 is positioned so that immediately above the roller 24 the belt 15 is inclined slightly to the vertical in the direction of the head pulley 16 ofthe belt 14.

A dancer roll 28 supported by weighted arms 29 pivotally carried by the frame 13 bears against the downward run of the belt 15, this maintaining the portion of the belt beween the roller 24 and the head pulley 17 under tension which ensures that the bags or sacks emerging from between the belts at the top are tipped over on to the generally horizontal or slightly inclined part of the belt 14, and are carried to a chute or further conveyor (not shown) contained within the boom 4, which delivers them to either one of two luffing and slewing loading conveyors arranged to discharge the bags or sacks on to lorries or trucks. The provision of two loading conveyors enables a full lorry or truck to be replaced whilst the bags or sacks are being discharged on to a second lorry or truck, thus ensuring continuous operation of the main unloading conveyor.

Control of the unloader can be undertaken from a cab (not shown) mounted at a high level on the machine, or by a pendant controller on the ships deck.

The wheels 26 of the bogies 2 are preferably retractable to allow the machine to rest on pads during an unloading operation.

As mentioned above the main power for raising the bags or sacks is provided by the motor M1 driving the head pulley 16 at the upper end of the belt 14. This is preferably a constant speed motor of appropriate power rating for the particular application of the unloader.

It has been found that an unloader as above described is highly suited for the unloading of bags of cement and like material from the holds of ships.

For such an application the rollers are preferably spaced apart a distance of approximately 450mm and the rollers 19 and supporting arms 20 are preferably arranged so that the rollers bear against the belt 15 with a force of about 35kg. In such an arrangement the belts are conveniently arranged to be driven at a speed of about 60 metres per minute.

It will, however, be appreciated that an unloader in accordance with the invention may be designed to deal with many different forms of bagged cargo, in addition to other items and also loose particulate material, and the roller spacing and the force that they exert on the belt 14 may be chosen to suit the particular form of cargo which the unloader is required to handle.

It will also be appreciated that the elevator may be supported in any other convenient manner, and in some cases the lower end may be arranged to telescope relative to the upper end to facilitate its introduction into, and withdrawal from the holds of ships.

Moreoverthe horizontal extension 23 at the lower end of the elevator may be dispensed with and replaced by a separate conveyor arranged to carry the bags or other items or material into the upwardly moving runs of the belts 14, 15. Where the elevator is employed for unloading bags or other similar items the separate conveyor may be arranged to deliver them to the elevator at an approximately constant rate corresponding to the most effecient rate of operation of the elevator.

In some cases movement of the arms 20 carrying the rollers 19 may be arranged to be damped utilizing any suitable form of damper units.

Although the invention has particular application to the unloading of cargo from the holds of ships it can also be used for loading purposes by driving the belts in the opposite direction. Then items fed on to the part ofthe belt 14 between the rollers 16,24 will be carried between the belts and carried down by them into the hold of a ship, where they can be removed from the lower horizontally extending part of the belt 14, or alternatively fed on to a further conveyorfortransporting to a difficult partofthe hold.

Claims

1. Cargo handling equipment for loading or unloading separate items or loose particulate mate rial into orfrom the holds of ships comprising a support structure, and an elongate elevator unit capable of being raised and lowered with respect to the support structure so that an end of the unit can be introduced into the hold of a ship with the opposite end projecting upwards therefrom, the unit incorporating a pair of opposed endless belts extending lengthwise along the unit, means for driving the belts so that adjacent runs travel in the same direction, a plurality of rollers spaced along the unit and biased against at least one of the two adjacent runs of the belts so as to urge it towards the other with a pressure such that items or material introduced between the two adjacent runs of the belts at the commencement of the run are carried between them to the opposite end of the run.

2. Cargo handling equipment according to Claim 1 for use in unloading items or material from the holds of ships wherein the adjacent runs of the belts are arranged to travel in the upward direction, and the rollers are arranged to be biassed against the upwardly travelling run of one of the belts so as to urge it towards the upwardly travelling run of the other belt with a pressure such that said items or material introduced between the adjacent runs of the belts at the lower end are carried upwards thereby, and discharged at the upper end, and means for conveying the items or material away from said upper end.

3. Cargo handling equipment according to Claim 2 in which at least one of the belts passes over an idling roller at its upper end and extends in a generally horizontal or slightly inclined direction for carrying the items or material to said conveying means.

4. Cargo handling equipment according to Claim 2 or 3 wherein the upper end of the elevator unit is carried by a boom capable of being raised and lowered about a horizontal pivot, and the means for conveying the items away from the upper end of the belts comprises a chute or conveyor extending along the boom.

5. Cargo handling equipment according to any preceding claim wherein the rollers are supported on pivoted arms which are inclined upward from the pivot axis towards the belt, so that the rollers are urged against the belt under the force of gravity.

6. Cargo handling equipment according to Claim 5 including means for supplementing or reducing the pressure of the rollers on the belt.

7. Cargo handling equipment according to any preceding claim including means for varying the pressure of the rollers on the belt.

8. Cargo handling equipment according to any one of Claims 1 to 4 incorporating hydraulically or pneumatically operated devices arranged to bias the rollers towards the belt.

9. Cargo handling equipment according to Claim 7 wherein the hydraulically or pneumatically operated devices are connected to a hydraulic or pneumatic pressure regulator respectively, which pressure regulator is adjustable to enable the pressure exerted by the rollers on the belt to be adjusted.

10. Cargo handling equipment according to any preceding claim wherein said other belt is associated with reaction rollers against which it is urged by the first said rollers.

11. Cargo handling equipment according to any preceding claim wherein the driving means is arranged to drive the belts at a substantially constant speed.

12. Cargo handling equipment according to any preceding claim for use in unloading items or material from the holds of ships, wherein the main drive is applied to a head pulley supporting the upper end of said other belt.

13. Cargo handling equipment according to Claim 12 wherein said other belt terminates at its lower end in a horizontal or near horizontal extends sion on to which items or material to be unloaded can be placed or fed.

14. Cargo handling equipment according to any preceding claim wherein at least one of the belts has projections on its operative surface which assist it to engage items or material to be carried thereby.

15. Cargo handling equipment according to any preceding claim wherein the support structure is provided with wheels for enabling it to be moved to different locations.

16. Cargo handling equipment according to Claim 15 wherein the wheels are retractable to enable the support structure to be lowered on to fixed pads in use.

17. Cargo handling equipment according to Claim 15 or 16 wherein at least some of the wheels are steerable.

18. Cargo handling equipment according to Claim 15, 16 or 17 wherein at least some of the wheels are coupled to a power unit to enable the equipment to be driven.

19. Cargo handling equipment substantially as shown in and as hereinbefore described with referpence to Figures 1 to 4 of the accompanying drawing.