The present invention relates to a method of packaging and unpackaging involving the use of a resilient envelope which is pressurised against and adapts to the shape of the cargo within the said envelop and which can be removed from the cargo with the assistance of negative pressurisation.

Numerous methods of packaging have hitherto previously been used wherein a resilient envelope has been employed to adapt to the shape of the cargo to be restrained. Many of the known methods of envelope packaging involve the application of a vacuum to the space in which the cargo is to be held. For instance, Australian Patent Application No. 34624/68 relates to a container for carrying goods having an inflatable envelope made partly of wholly of a flexible impermeable material adapted to enclose a space. The material of the envelope closely follows the surface of the cargo but the material is initially larger than the cargo and is drawn onto the surface so that expansion of the material such as occurrs with dunnage bags need not be involved. An alternative prior art method of packaging relates to the use of inflatable dunnage bags as has been disclosed in Patent Application No. 43255/68 by Interlake Steel Corporation and also in Patent Application No.

40905/72. In this method, the inflatable bags which are made from a resilient material are pressurised such that the resultant expansion of bag causes the wall of the bag to impinge upon the cargo which is intended to be stowed. A disadvantage of the use of a dunnage bag is that some items of cargo may remain loose in the carrying containers as the dunnage bag applies localised pressure to a portion of the cargo only. It has not previously been known to use an inflatable pillow which possesses a membrane which is able to conform to the shape of a load confined by such membrane.

A further prior art method of storage is disclosed in application No. 49984/69. This application discloses the combined use of pressurisation of an envelope

together with the coincident application of a vacuum to a space inside the envelope so that the envelope material adapts to the shape of the cargo to be secured.

A disadvantage of the latter method is that air reticulation access to the inside and outside of the envelope is necessary to achieve the combined simultaneous actions for pressurisation and suction.

The present invention provides a method of packaging utilising a flexible envelope contained within an enclosed vessel and which adapts to the peripheral shape of the cargo when pressurisation is applied to a space external to the flexibleenvelope and which can also be removed from the cargo by the application of a negative pressure to the same space. The envelope is adapted to enclose differing volumes depending upon the volume of the cargo and the amount of pressure applied to the outside of the envelope

On the application of a negative pressure to the outside of the envelope, the envelope is withdrawn from the cargo until it lies against the wall of the enclosed vessel.

Throughout the specification, the envelope will refer to the membrane which lies against the enclosed vessel and which contains the cargo when pressure is applied.

The inside of the envelope will refer to that space in which the cargo is held. The outside of the envelope will refer to that space between the flexible envelope membrane and the enclosure vessel or alternatively to the space between the oveable membrane and a membrane which lines the internal surface of the enclosure vessel or container.

The present invention is designed for containment of articles of regular or irregular shape to prevent movement during transit by rail, road, sea or air. The movement of the articles is prevented by pressurisation of a space between the enveloping flexible membrane and an optional lining membrane which lines the internal wall

The flexible enveloping and lining membranes form a

sealed bag and may be fabricated from a resilient rubberised or reinforced PVC sheet material. The membranes may be joined by stitching or welding or both. The active membrane or enveloping membrane is ideally elasticised to a degree according to requirement The lining membrane or passive membrane does not necessarily require the property of elasticity.

It is an object of the present invention to provid an improved packaging system which does not require air inlet and exhaust contact with the inside of the packaging envelope, but rather applies pressure external to a space occupied by the cargo. The flexible envelope material can be formed as a single membrane for the whole vessel or from a number of separate membranes which form sealed bags.

In its broadest form the present invention comprises a pressure packaging system comprising: an enclosure vessel for holding cargo therein, a resilient flexible membrane disposed between the wall of the vessel and the said cargo forming an envelope, wherein when a positive pressure is applied to a space between the said membrane wall and the said membrane, the membrane is urged against the said packaging such that it conforms to the peripheral shape of the cargo so enveloped; and wherein when a negative pressure is applied to the space between the membrane and the vessel wall the membrane is urged away from the cargo in the direction of the vessel wall thereby releasing the said cargo. In another form the ivention comprises: ^'

A pressurisation packaging system comprising: a vessel for holding cargo therein; at least one airtight bag disposed between the said cargo and the inner wall or walls of the said vessel; said airtight bag comprising a flexible membrane and a lining membrane such that the lining membrane is in opposition with or near the wall or walls of the said vessel and the flexible membrane is disposed between said cargo and said lining membrane, said system also

comprising means for applying a positive and/or negative pressure to an airtight space so formed between said membranes, wherein when a positive pressure is applied to the said space the flexible membrane moves relative to said lining membrane such that the flexible membrane is urged against the said cargo so that it conforms to the peripheral shape of the cargo thereby enveloping and containing said cargo and when a negative pressure is applied to the said space the said flexible membrane is urged away from the said cargo towards the lining membrane thereby releasing said cargo.

In one embodiment, the packaging system is used in conventional container vessels. The enveloping membrane forms a pillow and is adapted such that when it is not in use it aligns the inside wall of the vessel. Preferably there are at least three separate membranes one on each of the sidewalls of the vessel and one on the ceiling of the vessel. In another embodiment the membrane is continuous along the length of the walls and ceiling of the vessel and one pillow only is formed in the vessel. In the preferred embodiment the pillow is formed from an active flexible membrane and a vessel wall lining membrane such that an airtight space is formed between the membranes. The present invention will now be described in detail according to a preferred but non limiting embodiment with reference to the accompanying illustrations wherein:

Fig. 1 depicts an end view of a container having an envelope membrane located adjacent to its inner walls and ceiling according to the preferred embodiment;

Fig.2 Depicts an end view of a container vessel wherein the flexible membrane is pressurised against the cargo located within the container; and Fig. 3 Shows a detailed view of the means of connection of the flexible membrane and wall lining membrane according to a preferred embodiment.

Referring to figure 1, there is shown a container or vessel 1 empty of cargo and containing deflated wall

bags or pillows 2 and 3 and a deflated ceiling pillow 4. Each of the pillows when inflated act to restrain cargo located within the container. The pillows are preferably constructed of a flexible membrane made from a rubber impregnated laminated nylon fabric. The typical pillow i comprised of a base layer or lining membrane 5 which lie adjacent to the corresponding inner surfaces of the container 1 and a moveable or active membrane 6 (see Figure 3). The latter membrane 6 is proportioned so that it has sufficient slackness and elasticity to enable it to- respond to inflation and conform to the shape of at least one side of cargo within the container.

The container 1 preferably comprises a rigid framework which is either airtight or non-airtight. If the container is made airtight the envelope need only have the moveable membrane 6 to achieve the result of containing the cargo. This means that the lining membrane 5 can be eliminated.

Ideally, the pillows are formed from the passive lining membrane 5 and an active flexible membrane 6 so that airtightness is guaranteed and reliance is not placed on the aritightness of the container 1.

Conventional containers are generally rectangular and these containers are suited for the adaption of this packaging system. It is conceivable that the container could be any one of a multiplicity of possible shapes as the flexible nature of the moveable membrane 6 allows conformity within the shape of the walls and ceiling of the container when the pillows are either inflated. It is conceivable that the vessel or container 1 hereinbefore referred to could comprise a rail car, boat hull compartment, aeroplane compartment or like storage vessel.

Figure 2 shows an end view of the container 1 with the cargo 7 being enveloped by the pillows 2, 3 and 4, all of which are shown in the inflated mode.

It can be seen from figure 2 that the moveable membrane of each pillow conforms to the shape of the respective faces of the cargo which have been presented

to them as air pressure is applied within the spaces 2a, 3a and 4a between the said membranes.

In use, a typical container 1 is first loaded with cargo to the desired volume. Once the cargo is set in position pressure is applied to the internal spaces of each pillow by means of a standard air pump/evacuator (not shown) . Flow of air will be regulated according to conventional means and is introduced from an air source via a reticulation which delivers air to each bag or pillow according to preprogrammed requirements.

When cargo is to be unloaded the pressurised air in each of the pillows is evacuated to create a vacuum. This draws the moveable membranes 6 away from the cargo thereby releasing the cargo for unpacking. Although figure 2 shows three separate pillows, in an alternative embodiment (not shown) there is a single pillow which has a membrane corresponding to membrane 5 aligning all of the walls and ceiling of the container as well as a flexible moveable membrane corresponding to membrane 6 enveloping the whole cargo.

The pillows are pressurised by utilisation of a pressurisation system according to conventional means and comprising according to one embodiment an electric motor linked to a reticulation system for evacuation of and pressurisation of each pillow. Inflation and deflation of each pillow can be programmed individually or collectively according to requirements.

Alternatively, positive and negative pressurisation of the pillows can be achieved by use of stored pressurised gas according to conventional means (not shown) . Deflation of the pillows is induced by use of venturi valves exhausted to the atmosphere.

The pressurisation system is adapted for operation at very low pressures preferably within the range 0.1 to 1.5 p.s.i. A conventional regulator is used for pressure setting and maintenance of uniform pressure. In use, an operator presets the desired pressure on a calibrated dial within the aforesaid pressure limits depending upon the nature of the cargo to be packaged.

It is preferable that pressure limits be maintained where loads are such that varying pressure requirements are to be maintained across the load. The system allows for a variation in the pressures applied to the membranes of each bag according to cargo characteristics. For instance, if a load is top heavy the restraining active membrane or membranes at or near the top of the cargo would be pressurised to a value at or near the upper pressure limit. This is carried out by use of a known differential pressure controlling means.

According to a preferred embodiment the inflation or deflation is operable by means of electrical switching linked to shut off solenoids which are in turn linked to pressure sensors. The solenoids act to seal the pipe reticulation after pressurisation or exhaust of the pillows.

Figure 3a shows an enlarged view of the pillow and in particular the means for affixation of the membranes of the pillows to each other and also to the container wall.

Figure 3a shows a portion of a pillow 8 in the inflated mode. The membranes 5 and 6 are coupled at their respective edges according to one embodiment by means of eyelets or clamps 9. The membranes are folded to effect airtight sealing and the eyelets are spaced at suitable intervals to maintain the seal. Additional eyelets 10 and 11 are utilised according to requirements. Figure 3b shows the same portion of the pillow 8 in the deflated mode. In this instance the moveable membrane 6 is collapsed against membrane 5 thereby adopting a position to facilitate release of the cargo.

The pillows are fixed to the inside walls and ceiling of the container 1 preferably by a toggle pin arrangement or other conventional fastening means. The reticulation network which supplies the air would lie adjacent to or near the vessel, to link the air supply means to the spaces 2a, 3a and 4a.

The air pump/evacuator (not shown) is connected via feed lines to the space within each pillow according to

conventional reticulation means.

It will be recognised by persons skilled in the art that numerous variations and modifications can be made to the invention without departing from the spirit and scope of the invention as broadly described herein.