GB2229165A - Improvements in containers - Google Patents

Abstract

A haulage container, suitable for use as a field hospital unit in disaster relief, has a wheeled undercarriage (20, 21) for enabling the container to be towed. The undercarriage is retractable into the underside of the container by e.g. a hydraulic jack (26) to permit the container to be supported on its own base, and to reduce the overall height of the container. The container can be transported using conventional equipment designed for haulage containers but does not need a trailer on arrival at its destination. Chamber (26a) of the jack (26) is connected to a gas spring accumulator (32), via a damping control (34), and the ride height can be altered by a valve (38). A retractable bump stop (40) is mounted on a pivotable arm (42) under the control of a further hydraulic jack (46) whose hydraulic fluid supply is controlled by a valve (44). <IMAGE>

Description

IMPROVEMENTS IN CONTAINERS The present invention relates to a haulage container.

Large containers are frequently used in haulage and are transported by ship or aeroplane to remote locations. On land, the containers are transported by means of trailers.

In certain applications, it may be difficult to find suitable transportation for the container at the destination. For example, such containers may be used to assist in disaster relief in which case the containers may be used for carrying supplies or as a field hospital unit. Because disasters can occur in poor and remote locations, local transportation may not be available for the container on its arrival at its destination.

With a view to mitigating this problem, the present invention provides a haulage container having a wheeled undercarriage for enabling the container to be towed, wherein the undercarriage is retractable into the under-side of the container to permit the container to be supported on its own base, and to reduce the overall height of the container.

The headroom available for cargo in many aeroplanes is not sufficient to enable storage of a container and its trailer. Even aboard ships, when headroom is not a limiting factor, containers are usually stacked and need to conform to a given size. The present invention, by providing a retractable undercarriage, permits the container to be handled using conventional equipment but still removes the need for a trailer when the container arrives at its destination.

Preferably, a hydraulic jack is provided on the undercarriage to permit the latter to be lowered and raised.

The hydraulic jack may act as part of a hydro-pneumatic suspension for the container when the latter is being towed, the jack being connected in circuit with a gas spring accumulator.

Conveniently, the individual wheels of the container may be mounted on swinging arms pivotable about fixed axles mounted on the under-side of the container. The axles are advantageously located within a compartment on the under-side of the container which is surrounded by a sub-frame on which the container may be supported.

To prevent bottoming of the container in the event of a fault developing in the suspension, movable bumps stops may be provided to limit the movements of the suspension when the wheels are lowered. The bump stops may be mounted on arms which are piyotable between an operative and an inoperative position by means of a hydraulic jack.

If the container is to be used as a field hospital unit, then it will contain its own power supply and generator.

The same generator may serve to power the hydraulic pump(s) needed for raising the undercarriage and for the suspension. Alternatively, a motor driven pump may be provided for this purpose.

In the preferred embodiment of the invention, an electronic control circuit is provided for ensuring that the various valves and pumps in the hydraulic circuit are operated safely and in the correct sequence.

The invention will now be described further, by way of example, with reference to the accompanying drawing which is a schematic diagram of the suspension and undercarriage of a container in accordance with the invention.

The container of the preferred embodiment of the invention is intended for use as an operating theatre to be transported by aeroplane to a disaster area, for example an earthquake region. The outer dimensions of the container are standard so that with its undercarriage retracted it outwardly resembles any conventional road haulage container and can generally be handled in the same manner. The container can therefore the transported in conventional ships and aeroplanes without any alteration to their loading and unloading gear.

If the container is to be transported by aeroplane, it is important that it should be able to rest on its base without any part of the undercarriage protruding. This is not only on account of the restricted headroom but also because even loading is required on the floor of the aircraft.

A sub-frame extends downwards from the container around its entire perimeter and defines a shallow open compartment on the under-side of the container in which two fixed axles are recessed. Recesses are also provided within the container to accommodate the wheels when they are retracted. The provision of recesses for the wheels does intrude slightly on the space available within the container but does not prevent the container from being used as a field hospital unit.

On arrival at its destination by sea or air, the undercarriage is lowered and the container is then supported on its own wheels and does not require a trailer. It can be towed using a tractor and in extreme cases may even by pulled by horses or oxen.

As it is intended for a field hospital, the container includes a generator to be used as a power supply.

However, it is not essential that the container be designed for this use and a generator (internal combustion engine) may be provided exclusively for the purpose of generating the hydraulic pressure required by the retractable undercarriage and the hydro-pneumatic suspension.

The internal combustion engine drives a pump 10 of which the input is connected to a reservoir tank 12 and the output line is connected to a pressure regulator 14. The regulator maintains a constant supply pressure in a line 16 and a pressure accumulator 18 serves to stabilise the pressure in the line 16 when hydraulic fluid is taken from it by the various elements of the hydraulic circuit to be described below.

One of the wheels 20 to be raised and lowered is mounted on one end of a trailing or leading swinging arm 22.

The arm 22 is pivoted about a fixed axle pivot 24 and has a bellcrank lever 28 connected to a hydraulic jack 26. The jack 26 is a double acting jack having two working chambers 26a, 26b connected to a control valve 30. The main working chamber 26a is further connected to a gas spring accumulator 32 by way of a damping control 34 and by way of a shut-off valve 36 to a levelling valve of which the valve spool is responsive to the position of the bellcrank lever 28. The levelling valve 38 and the control valve 30 are connected to drain and to the pressure supply line 16.

A retractable bump stop 40 is provided on a pivotable arm 42 to limit the suspension travel when the trailer is being towed. The arm 42 is pivoted by a further hydraulic jack 46 to which the supply of hydraulic fluid is controlled by means of a valve 44.

The valves 44 and 30 are both three position valves with a neutral centre position. If moved in one direction, pressure is supplied to one output line while the other is connected to drain. If moved in the opposite direction, the connections are reversed. The normal positions adopted by both valves are the neutral positions in which the input and output lines are not connected to one another.

The wheel 20 is shown in the position where it is resting on the ground and supports the weight of the container. In this mode of operation, the valve 30 isolates the jack 26 from the pressure supply line 16.

If the wheel attempts to rise on hitting a bump in the road surface, fluid is pumped out of the working chamber 26a into the gas spring accumulator 32 to compress the gas in the latter. This movement is resisted by the air spring 32 and damped by the damping control 34.

The ride height or level of the trailer is altered by means of the valve 38. If the container is riding low then hydraulic fluid is pumped to the working chamber 26a of the jack 26 and conversely if the container is sensed by the linkage to the bellcrank lever 28 to be riding too high then the jack 26 is connected to drain by the valve 38.

In the illustrated condition, the bump stop 40 is in its lowered position in which it limits the travel of the swinging arm 22.

Assuming now that the undercarriage is to be retracted, the following operations are carried under the control of an electronic circuit. First the valve 44 is moved to its position in which it supplies hydraulic fluid to the jack 46 in a direction to retract the arm 42 and the bump stop 40.

Next, the shut-off valve 36 is operated in order to disable operation of the levelling valve 38 while the undercarriage is being retracted. Then the valve 30 is moved to allow fluid under pressure to flow from the working chamber 26a and to the chamber 26b thereby retracting the wheel 20 into the container.

Lowering the undercarriage consists essentially of a reversal of the steps described above for raising the undercarriage. After the pump has been operated for sufficient time to raise the pressure in line 16 and charge the pressure accumulator 18, the valve 30 is operated to apply pressure to the working chamber 26a and relieve the chamber 26b. The shut-off valve 36 is next opened to bring the levelling valve 36 into operation and lastly the bump stop 40 is lowered into position by the valve 44 being operated to supply fluid under pressure to the jack 46.

Claims (10)

1. A haulage container having a wheeled undercarriage for enabling the container to be towed, wherein the undercarriage is retractable into the underside of the container to permit the container to be supported on its own base, and to reduce the overall height of the container.

2. A container as claimed in claim 1, wherein a hydraulic jack is provided on the under-carriage to permit the latter to be lowered and raised.

3. A container as claimed in claim 2, wherein the the hydraulic jack acts as part of a hydro-pneumatic suspension for the container when the latter is being towed, the jack being connected in circuit with a gas spring accumulator.

4. A container as claimed in any preceding claim, wherein the individual wheels of the container are mounted on swinging arms pivotable about fixed axles mounted on the under-side of the container.

5. A container as claimed in claim 4, wherein the axles are located within a compartment on the under-side of the container which is surrounded by a sub-frame on which the container may be supported.

6. A container as claimed in any preceding claim, wherein, in order to prevent bottoming of the container in the event of a fault developing in the suspension, movable bumps stops are provided to limit the movements of the suspension when the wheels support the container.

7. A container as claimed in claim 6, wherein the bump stops are mounted on arms which are pivotable between an operative and an inoperative position by means of a hydraulic jack.

8. A container as claimed in any preceding claim, wherein an electronic control circuit is provided for ensuring that the various valves and pumps in the hydraulic circuit are operated in the correct sequence.

9. A haulage container constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.

10. A field hospital unit housed within a transportable haulage container as claimed in any preceding claim.