Abstract:
A method of securing a flexible plastics liner ( 12 ) within a cargo container ( 10 ) uses a plurality of plastic retaining cords ( 17 ). Each cord ( 17 ) is either attached to the liner ( 12 ) at a suitable position ( 14 ), or is passed through a loop ( 43 ) (FIG.  9 ) or other receptor ( 31 ) (FIG.  8 ) secured to the liner. Each cord ( 17 ) has a self-jamming cleat ( 23 ) secured at or adjacent one end, to permit the cord to be coupled to a member ( 20 ) provided within the container ( 10 ) and then tensioned so as to suspend the liner therewithin. The cord may be passed through a hole ( 19 ) in the member ( 20 ) or a loop may be formed around the member ( 30 ) (FIG.  8 ) or ( 41 ) (FIG.  9 ).

Description:
TECHNICAL FIELD 
     This invention relates to a method of securing a flexible plastics material liner within a container, and also to a liner adapted for securing within a container. The invention further relates to the combination of a container and such a liner secured therewithin. 
     BACKGROUND OF THE INVENTION 
     Cargo containers, typically 7 m or 14 m long, are very widely used for the transport of goods by road, rail and sea. Such containers can be used for the transport of flowable solid products, such as powders, granules or other pulverulent materials. For this purpose, it is known to provide a flexible plastics material bag of a shape and size generally corresponding to the container interior, which bag is suspended in the container to serve as a liner. The products to be transported are then loaded into the bag, the container itself providing the required strength to permit the transportation, while the liner prevents leakage of the product. The liner may have an outlet opening which is held closed until the products are to be discharged, or the liner may simply be cut open, over a discharge hopper. 
     The fitting of a liner to the interior of a container must be performed carefully in order to avoid areas of high stress which could lead to tearing of the liner when the container is being used for the transport of goods. It is thus time consuming to suspend a liner appropriately within a container and subsequently to release a liner after use from a container, and in order to minimise the time required, various suspension techniques have been developed. Many of these techniques need the use of various hand or even power tools and require considerable care, in order to ensure the liner is not punctured or torn during installation, and will remain intact during loading of the product and the transportation thereof. However, during emptying, the liner should remain in its installed position and not tear or leak, other than at the discharge opening. 
     SUMMARY OF THE INVENTION 
     It is a principal aim of the present invention to provide a method whereby a flexible plastics material liner may relatively easily and quickly be secured within a cargo container, and also a liner suitable for securing within a cargo container by this method. 
     According to one aspect of the present invention, there is provided a method of securing a flexible plastics material liner within a cargo container using a plurality of retaining cords each associated with a respective self-jamming cleat, which method comprises the performance in any order of the following steps: 
     locating the liner within the cargo container; 
     coupling each cord to a respective predefined position on the liner; 
     coupling each cord to a respective attachment member provided within the container; and 
     engaging each cord with its associated self-jamming cleat for locking thereby; 
     whereafter each self-jamming cleat is moved along its respective cord so that the cord comes under tension so as thereby to secure the liner within the container. 
     It will be appreciated that by the method of this invention, a liner may be suspended and secured within a cargo container using a plurality of retaining cords each of which is secured in position by means of a self-jamming cleat locked on to the cord. The method may be performed in a number of different ways, each having its own advantages. These ways include the following. 
     1. The cords may be coupled to the liner at the appropriate positions during the manufacture thereof and self-jamming cleats engaged with the cords. Then, when the liner is opened out and secured within a container, the cords are ready for use, to be coupled to appropriate members within the container. 
     2. The cords and cleats may be supplied separately from the liner to the liner installer, who may connect the cores at appropriate positions on the liner having regard to the container configuration immediately before installing the liner in a container. 
     3. During the manufacture of the liner, it may be provided with suitable receptors such as plastics material loops, through which the cords may subsequently be passed. The cords may then be coupled to members within the container, before the liner is installed, the cords being passed through the receptors on the finer as the liner is opened out. In this case, the self-jamming cleats may be pre-positioned on the cords, or may be fitted to the cords at the time of installing the liner in the container. 
     The method of this invention, using cords and self-jamming cleats, allows a liner to be secured to a container in a simple and efficient manner without the need for any hand tools. Thus, an operator is most unlikely to attempt to secure the liner in position other than in the pre-determined manner, using the cords, so reducing the likelihood of the liner tearing in use. Following the transport and unloading of products from the liner, it is a relatively easy matter to release the self-jamming cleats and so free the liner from the container, for disposal or recycling. 
     A particular advantage of the third possibility mentioned above is that on removing a used liner from a container, the cords may be left in the container ready for re-use with a fresh liner. In addition, the used liner will consist only of the plastic material from which it was originally made and this significantly enhances the recycling value of the liner. 
     In a case where the cords are attached to appropriate sites of a liner, during the manufacture thereof, or receptors for the cords are similarly attached, reinforcement may be added to those sites in order to minimise the likelihood of the liner tearing during use. 
     In a case where the cords are attached to a liner during the manufacture thereof, one end of each cord may be secured to the liner, with a self-jamming cleat provided at or adjacent the other end of the cord. In this case, to install a liner in a container, the cords may be passed through respective holes formed in members within the container, whereafter the self-jamming cleats are moved along the cords to engage a face of the respective member remote from the liner and thus suspend the liner from that member. Each hole may be large enough to allow the cord and cleat to be passed therethrough. Alternatively, the cord alone may be passed through the hole and the cleat then re-engaged with the cord. 
     Another possibility is for the cord to be secured to the liner part way between its ends, with the self-jamming cleat provided on one of the end portions, ready for engagement by the other end portion. In this case, the two cord portions may be passed round a member within the container whereafter the self-jamming cleat is used to lock together the two end portions. This technique may also be used when the liner is provided during manufacture with a receptor for a cord, which is passed through the receptor at the time of installing the liner. 
     In the methods of this invention, at least some, but possibly all, of the cords are elastic. In this case, the application of tension to a cord during the installation of a liner as the self-jamming cleat is fastened in the required position on that cord will have the effect of exerting a pre-load on the liner. This will help to ensure the liner stays in the correct position, particularly prior to and during loading with products. 
     It is preferred that the cleat is retained adjacent one end of the cord for example by means of a stopper furnished on the free end of the cord. This helps to ensure the cord and cleat are ready for use, irrespective of whichever technique is employed to install the liner within a container, and also facilitates re-use of the cords, in a case where they are not permanently attached to a liner. 
     The arrangements described above allow a liner to be fitted particularly easily into a cargo container with the liner in the correct position, since the container may be furnished with attachment members at suitable locations, and the liner having predefined sites for the cords. In this way, one may be assured that the liner has properly been fitted with a minimum likelihood of tearing of the liner during fitting or during use. 
     According to a second aspect of this invention, there is provided a flexible plastics material liner for a cargo container which liner is provided with a plurality of spaced retaining cords attached thereto, in combination with a like plurality of self-jamming cleats, one for each cord respectively, whereby the liner may be secured within a container by coupling each retaining cord to a part of the container and engaging the respective self-jamming cleat with each cord to secure the cord to said member so that the liner is suspended from the cords. 
     Most preferably, at least some, but possibly all, of the cords are elastic. This allows a pre-load to be imparted to the liner, so assisting the positioning of the liner in the correct position. 
     Self-jamming cleats are known and widely used in the yachting industry, and particularly in relation to relatively small sailing boats and dinghies. Various of those known forms of cleat could be employed in the present invention, though a preferred embodiment is for the cleat to be generally elongate and have formed therein an elongate aperture configured to allow entrapment of the cord. For example, the width of the aperture could decrease from one end of the cleat towards the other end thereof, passing the cord through the wider end of the cleat and then pulling the cord towards the other end, the cord becomes jammed in the cleat. 
     In the alternative, or in addition, teeth may be provided within the cleat for inter-engagement with the cord, so as thereby to trap the cord. Other forms of cleat may be employed, such as a cleat having a snail cam co-operating with a fixed surface or a pair of snail cams defining a nip through which the cord passes. Other suitable designs of self-jamming cleat will be apparent to those familiar with, or by researching, the marine industry. 
     Any of a number of different techniques may be employed for attaching the cord to the liner. In order to assist that attachment, the cord may carry at its end a substantially rigid member such as a rod or tube. Then, strips of self-adhesive tape having a relatively aggressive adhesive may be laid over the end of the cord and over said substantially rigid member, or the cord may be passed through a hole in a retaining panel, which panel then may be welded or otherwise adhered to the main area of the liner, so as to trap the substantially rigid member between the liner and the panel. 
     Liners of this invention may be made of any of those plastics materials from which the known cargo container liners are conventionally made. For example, polyethylene is particularly suitable for this purpose. 
     This invention extends to the combination of a container and a liner of this invention as described above, which liner is retained in the required position within the container by means of cords passing through members of, or provided within, the container and being held under tension by self-jamming cleats provided on the cords and bearing on said members. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     By way of example only, one specific embodiment of the present invention will now be described in detail, reference being made to the accompanying drawings in which: 
     FIG. 1 is a diagrammatic view, partially cut-away, of a typical transport container having a liner fitted thereto in accordance with the present invention; 
     FIG. 2 is a detail view of one fixing for the liner shown in FIG. 1; 
     FIGS. 3 and 4 are respectively plan and under plan views on a preferred form of self-jamming cleat for use with the liner of this invention; 
     FIG. 5 is a detail view on one possible cord attachment to a liner, FIG. 5A showing just the end portion of the cord; 
     FIG. 6 is a detail view of an alternative cord attachment to a liner, FIG. 6A showing the end portion of the cord; 
     FIG. 7 shows a further alternative attachment, using a cord end as shown in FIG. 6A; 
     FIG. 8 is a detail view of an alternative fixing for the liner shown in FIG. 1; and 
     FIG. 9 is a detail view on yet another fixing for the liner shown in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring initially to FIG. 1, there is shown a cargo transport container  10  of an entirely conventional design and which typically may be approximately 7 m long, and approximately 2.4 m×2.4 m in cross-section. Such containers are used very widely, for the transport of goods by road, rail and sea. Though not shown in FIG. 1, end  11  of the container is normally fitted with a pair of doors, hinged one to each upright edge at the end of the container and which may be secured in a closed position. 
     In order to allow such a cargo container to be used for the transport of flowable solid products in bulk, such as powders, granules and other like flowable solids, the container may be fitted with a liner  12  fabricated from polyethylene sheeting, typically having a thickness of about 150 μm. The liner is secured to the container at various points in order to ensure that it stays in the required position not only during transport of a contained product but also during emptying of the product out of the doored end  11  of the container. Typically, a framework of four wooden members  13  may be provided within that doored end  11  of the container, to ensure that on opening of the doors, the liner will be retained in position within the container, even if products in bulk are being transported within the liner. 
     Fixings in accordance with the present invention are provided between the liner  12  and container  10 , both along the top of the container as shown at  14  and to the members  13  as shown at  15 . FIG. 2 illustrates one such fixing in greater detail. 
     Each fixing  14  or  15  includes an elastic shock-cord  17  having one end  18  attached to the liner  12  and passing through a hole  19  provided in a member  20  which forms part of or is furnished within the container. Said one end  18  of the cord  17  is attached to the liner  12  by means of strips  21  of self-adhesive tape, which pass over a short bar  22  attached to the end of the cord. 
     A self-jamming cleat  23  is arranged on the cord  17  and bears on the face of member  20  remote from the liner  12 , so as to prevent that cord running through the member and coming free thereof. The cleat is shown in greater detail in FIGS. 3 and 4 and comprises a one-piece plastics moulding having a generally elongate shape with an aperture  24  extending therethrough. The aperture opens into a slot  25  extending lengthwise of the cleat, which slot is furnished with opposed gripping teeth  26 . 
     The free end portion (not shown) of the cord  17  is provided with a stopper, which may take the form of a simple knot. This stopper should be formed on the end of the cord following threading of the cord through the aperture  24 , so as to prevent subsequent removal of the cleat from the cord. 
     In use, the container  10  is provided with the cross-members  15  in the doored end of the container and either holes are drilled through the container at appropriate positions or in the alternative members having holes at appropriate positions are secured within the container. Then, the liner is placed within the container and unfolded, the cleats and cords being passed through the appropriate respective holes in the members. Tension is then applied to each cord by pulling on its free end and the cleat is moved along the cord until it engages the side face of the member through which that cord passes. The cleat is then jammed on to the cord so as to keep the tension therein. 
     FIGS. 5 and 5A show in greater detail the attachment of end  18  of the cord  17  to the liner  12 . As can be seen, the cord is passed through a hole formed transversely in bar  22 , the end of the cord then being knotted to prevent the cord coming out of that hole. The application of strips  21  of self-adhesive tape having an aggressive adhesive over that bar and so as to adhere to the liner  12  will securely hold the cord  17  to the liner whilst also reinforcing that area of the liner and moreover distributing over an area of the liner any loads imparted to the cord. 
     An alternative arrangement is shown in FIGS. 6 and 6A. Here, a washer  27  is provided on the free end of the cord and again strips  21  of self-adhesive tape are employed to attach the washer to the liner  12 . Instead of using strips of self-adhesive tape, a panel  28 , also of a flexible plastics material, may be directly securerd to the liner  12  by one of a heat welding, chemical fusion or adhesive technique, the panel having a hole through which the cord passes so that the washer is located between the panel and the liner, as shown in FIG.  7 . Another possibility is to attach the washer to the inside of the liner, with the cord passing through a hole formed in the liner, the hole being sealed by at least the peripheral region of the washer being bonded to the liner interior. 
     FIG. 8 shows an alternative arrangement for fixing a liner to a wooden member  30  provided within a container (not shown). A bar  31  is secured to a face of a liner  32 , using strips  33  of self-adhesive tape in a similar manner to that described with reference to FIGS. 2 and 5. A single elastic shock-cord  34  is passed through the bar  31 , before that bar is taped to the liner, so that the bar is approximately in the central region of the cord. A self-jamming cleat  35 , similar to that shown in FIGS. 3 and 4 but having a through-aperture at the right hand end (in FIG. 3) of the cleat, is threaded onto one of the end portions  36  of the cord  34  and is retained thereon by means of a knot  37 . In order to prevent the cord  34  coming free of the bar  31  prior to the liner being installed, a further strip of tape (not shown) may be passed over the cord and bar. 
     In use, there is no need for a hole to be formed through member  30 , unlike the arrangement with the previous embodiments. Instead, the liner is secured to the member  30  by passing the two parts of the cord around the member and threading the other end portion  38  of the cord through the self-jamming cleat retained on the one end portion  36 . As with the previous embodiments, the liner may be tightened to the member  30  by pulling end portion  38  through the self-jamming cleat and locking the cleat on to that end portion at the appropriate position. 
     FIG. 9 shows yet another arrangement, similar to that of FIG.  8 . In FIG. 9, there is shown an upright  40  which is a part of a conventional cargo container, there being a plurality of such uprights spaced along the side walls of the container. Extending between the uprights and fixed thereto are several parallel horizontal bars one of which is shown at  41  in FIG. 9. A liner  42  to be secured in the container is provided with a loop  43  of plastic material, which loop is heat-welded to the external face of the liner. Extra reinforcement, for example using adhesive tape or further pieces of plastic sheet also welded to the liner may be employed. The liner should have a plurality of such loops, provided at those positions from which the liner should be suspended. 
     With the arrangement of FIG. 9, the liner may be supplied without any cords or cleats, these being provided at the time of installing the liner in a container. Then, when the liner is to be installed, respective elastic cords  44  each having a stopper knot  45  at one end and a self-jamming cleat  46  threaded on to the cord to lie adjacent the knot may be passed through the loops  43  on the liner. The liner is opened out in the container and the cords passed round appropriate bars  41 , threaded back through the associated cleats, pulled to be under tension, and then locked in the cleats by the self-jamming action thereof. 
     It will be appreciated that the cords could be threaded through the loops  43  during the manufacture of the liner. Alternatively, the cords could be passed round the bars  41  in the container, and left there ready for use when a liner is to be installed. 
     When the liner is to be removed, after transported product has been discharged, it is a relatively easy matter to release the cords from their respective self-jamming cleats and pull the liner free of the cords, leaving the cords in the container ready for use with a fresh liner. This has the advantage that the liner, when removed, may consist solely of the plastic material from which the liner has been made; the liner thus has enhanced recycling value, and the cost associated with installing a fresh liner is reduced.