This invention relates to enclosures for storing sheet documents.

It is a common requirement of the retail and banking industries to be able to move cash from one place to another securely. This role is often handled by "Cash-in-Transit" (CIT) companies. In a typical situation, a CIT company will collect cash from a retailer, load the cash into a suitable cross-pavement carrying case and load the container onto a fortified van for onward conveyance to a final destination. There are multiple opportunities for pilfering and tampering with cash between the cash tills at the retailer and the final destination.

We have developed a system, described in our PCT application W02010/125372, for providing a cost-effective, tamper evident enclosure for cash. This system can be retrofitted to existing cash handling equipment and uses a heat sealer to seal plastic bags into which cash has been deposited by the cash handling equipment. The system offers a means of securing cash, whereby any attempt to tamper with the enclosure after sealing will be immediately apparent. However, there are situations where the extra bulk and cost of a heat sealer are not acceptable.

Our previous enclosure for sheet documents, described in our PCT application

W02011/138594, addresses these issues. The enclosure disclosed in W0201 1/138594 is a disposable bag with a sliding seal. The enclosure can only be removed from cash handling equipment when the sliding seal is inserted. The sliding seal cannot then be removed without causing visible damage. Thus, any tampering with the sealed enclosure to expose the contents will be immediately evident.

However, the sliding seal can easily become lost before it is used and it is extremely difficult to arrange for automatic insertion of the sliding seal by cash handling equipment to close the enclosure. Thus, manual insertion of the sliding seal is, in practice, required. In accordance with a first aspect of the invention, there is provided an enclosure for storing sheet documents comprising a bag, to which is affixed a sheet document receiving port comprising a frame and a shutter captive in the frame and irreversibly moveable relative to it from an open position in which sheet documents can pass into the bag through an aperture in the frame to a closed position in which the shutter occludes the apertures.

By providing a shutter captive in the frame that is affixed to the bag, the shutter and frame are inseparable. The shutter cannot therefore be lost and it is relatively straightforward to arrange for an automatic closure mechanism to close the shutter. The above-mentioned problems are therefore overcome by the invention.

Typically, the sheet documents pass into the bag through an aperture or slit formed in the bag in alignment with the aperture in the frame.

In a preferred embodiment, the shutter is rectangular and moves from the open to the closed position in a direction perpendicular to the longest edge of the shutter's rectangular shape.

This embodiment is advantageous because the shutter protrudes by only a small amount (compared to a variant where the shutter moves from the open to the closed position in a direction parallel to the longest edge of the shutter's rectangular shape) when in the open position. Furthermore, in this embodiment the shutter protrudes such that it lies adjacent the bag beneath the frame (rather than alongside it) when in the open position so occupies hardly any additional space within the cash handling equipment. This location of the shutter makes it straightforward for a closing mechanism to engage the shutter and close it automatically.

Typically, the frame comprises one or more locking elements that automatically engage with the shutter when in the closed position to prevent it moving to the open position. Preferably, the or each locking element engages with an edge of the shutter when in the closed position. The edge is normally an undercut edge in the shutter, formed for example by a pair of recesses in the shutter.

In a preferred embodiment, the or each locking element comprises a tab, which is resiliently displaceable from a projecting position to a retracted position to allow the shutter to move from the open position to the closed position and which returns to the projecting position to engage with the shutter when in the closed position.

The shutter typically comprises a recess corresponding to the or each tab to accommodate the or each tab in the projecting position when the shutter is in the closed position. This arrangement allows the tabs to adopt the projecting position whilst the shutter is in the open position, which prevents them from being conditioned to being in the retracted position so that they only return to the projecting position slowly when the shutter is in the closed position. If the tabs were to become conditioned in this way it could present an opportunity for someone to close the shutter, remove the enclosure and then open the shutter before the tabs had returned to the projecting position.

The receiving port normally comprises one or more frangible shear pins, which engage with the shutter when in the open position to prevent unintended movement of the shutter from the open to the closed position. The shear pins may engage with a leading edge of the shutter when it is in the open position.

Typically, the frame comprises first and second elements, the shutter being trapped between them in a recess in the first element. The first and second elements will usually be disposed outside the bag. Normally, the frame comprises outer and inner sections disposed outside and within the bag respectively. The outer section of the frame preferably comprises the first and second elements.

The outer and inner sections of the frame may be joined by an array of pegs passing through corresponding holes, the pegs having flared ends to prevent the outer and inner sections from separating. The array of pegs may form part of one of the outer and inner sections and the holes may form part of the other of the outer and inner sections. Alternatively, the array of pegs and the holes may form part of each of the outer and inner sections.

A first group of the array of pegs is preferably integral with the first element, each peg in the first group passing through corresponding holes in the second element and the inner section. This ensures that the first and second elements cannot be separated without damaging them. Thus, any attempt to gain access to the shutter will be evident.

In addition, a second group of the array of pegs may be integral with the second element.

The outer section of the frame may comprise first and second elements, the shutter being trapped between them in a recess in the first element.

Preferably, one of the outer and inner sections comprises a groove and the other of the outer and inner sections comprises a projecting rim that is located within the groove to trap the bag between the outer and inner section. The arrangement of the groove and projecting rim forms a labyrinth when they are brought together within which the bag is trapped. This makes it impossible to tease the bag out from between the sections of the frame to gain access to the contents and then feed it back between them afterwards.

An embodiment of the invention will now be described with reference to the

accompanying drawings, in which: Figure 1 shows an exploded front view of part of an enclosure according to the invention; and

Figure 2 shows an exploded rear view of the part of the enclosure shown in Figure 1.

The exploded views of Figures 1 and 2 show a bag 1 and a sheet document receiving port comprising a frame and a shutter 2. The frame is made up of three separate components: an inner section 3, and an outer section comprising a first element 4 and a second element 5.

The bag 1 is typically formed to have block ends (i.e. ends with a rectangular or square shape) with gusseted sides. The block ends allow the bag to adopt a rectangular or square cross-section, which is well suited for sheet documents, such as banknotes, to be stacked inside. The gusseted sides allow the bag to be folded flat for storage.

To assemble the enclosure, the bag 1 is first formed with one closed end and one open end. Then the outer section of the frame is assembled by sandwiching the shutter 2 between the first and second elements 4, 5. Correct registration between the first and second elements 4, 5 is ensured by a set of six pegs 6a-6f on the first element 4, which pass through a corresponding set of holes 7a-7f in the second element 5. Together with another set of six pegs 8a-8f on the second element 5, the six pegs 6a- 6f pass through a set of twelve holes 9a-9l punched in the bag 1 and another set of twelve pegs 10a-10l in the inner section 3, which is passed into the bag 1 through the open end. A heat tool is then inserted through the open end of the bag 1 and into engagement with the inner section 3. The heat tool then melts the ends of the pegs 6a- 6f and 8a-8f so that the pegs 6a-6f and 8a-8f cannot be withdrawn from the holes 10a- 101 and outer section and inner section 3 of the frame are held fast together. In this way the frame is affixed to the bag 1. The open end of the bag 1 is then sealed and an aperture 1 1 cut in the bag.

The aperture 1 1 is in alignment with apertures 12, 13, 14 in the first and second elements 4, 5 of the outer section of the frame and the inner section 3 of the frame. A projecting rim 15 around the aperture 14 in the inner section 3 of the frame is aligned with a groove 16 formed around the aperture 13 in the second element 5 of the outer section of the frame. The rim 15 and groove 16 form a labyrinth in which the material of the bag 1 is trapped. This makes it impossible for someone to attempt to tease the bag 1 out from between the inner section 3 and outer section of the frame to gain access to the contents and then reinsert the bag afterwards. Any attempt to do so will leave clear evidence of tampering.

The assembled bag 1 can be inserted into cash handling equipment such as a banknote counter or sorter to receive banknotes discharged by the equipment during a processing operation. Typically, the equipment will have a retaining mechanism for retaining the bag 1 until the shutter 2 has been closed. At that point, the retaining mechanism will release the bag 1 so that it can be removed from the equipment.

Banknotes discharged by the equipment are fed from a transport in the equipment through the apertures 1 1 , 12, 13 and 14 into the interior of the bag 1. When the bag 1 has received a desired quantity of banknotes, the shutter 2 is then closed to seal the bag 1. The closure of the shutter 2 may be carried out manually or by a closure mechanism in the cash handling equipment. This will typically involve a ram or rotary cam pushing against a ledge 17 on the shutter 2 so that it runs along a rebate formed around the inside of aperture 12 on the first element 4 of the outer frame into a closed position in which the shutter 2 occludes the apertures 1 1 , 12, 13 and 14. The shutter is provided with a slot 18 to allow it to slide past peg 6e.

A pair of tabs 19a, 19b are displaced into corresponding recesses 20a, 20b in the second element 5 of the outer frame by the shutter 2 as it moves into the closed position. When the shutter 2 is in the closed position the tabs 19a, 19b return to a projecting configuration and bear against an edge of the shutter 2 undercut by a pair of recesses 21 a, 21 b formed in the shutter 2. Thus, the shutter 2 cannot be withdrawn to the open position. In this way, the movement of the shutter 2 from the open position to the closed position is made irreversible. Any attempt to open the shutter 2 will cause damage to the shutter 2 or tabs 19a, 19b, which will be immediately evident. The tabs 19a, 19b are formed of the same material as the second element 5 of the outer frame. The junction between the tabs 19a, 19b and the second element 5 forms a natural hinge. The tabs 19a, 19b are urged naturally into the projecting position shown in Figures 1 and 2 but can be pushed into a retracted position within the recesses 20a, 20b as discussed above. When the shutter 2 is in the open position the tabs 19a, 19b lie within recesses 22a, 22b in the shutter 2. This allows the tabs 19a, 19b to adopt their projecting position, which prevents them from becoming conditioned to being in the retracted position. This ensures that they spring back from the retracted position to the projecting position quickly so that there is no opportunity for pilfering by someone closing the shutter, removing the bag 1 from the cash handling equipment and then opening the shutter before the tabs 19a, 19b had returned to the projecting position.