WO1998043827A1

WO1998043827A1 - A binder assembly

Info

Publication number: WO1998043827A1
Application number: PCT/GB1998/000935
Authority: WO
Inventors: Philip John Chidlow
Original assignee: International Masters Publishers Limited
Priority date: 1997-04-01
Filing date: 1998-03-27
Publication date: 1998-10-08
Also published as: GB2323815B; GB2323815A; AU6844998A; GB9706575D0

Abstract

The present invention provides a binder assembly (110) comprising: at least one page holder (20) comprising a page holding portion (50) for holding one or more pages and a first retaining portion (60) for retaining the page holder (20) in a binder element (10); and a binder element (10) for retaining said at least one page holder (20), the binder element (10) comprising a plurality of second retaining portions (80), each second retaining portion (80) being arranged to cooperate with the first retaining portion (60) of one of said page holders (20) to retain that page holder (20) in the binder element (10); wherein the first (60) and second (80) retaining portions have complementary interlocking shapes to enable the page holder (20) to be slidably moveable to a retained position in the binder element (10) by relative movement of the first and second retaining portions in a first direction, and removal of the page holder (20) from the binder element (10) in a direction perpendicular to the first direction is resisted, and one of the first and second retaining portions comprises a protrusion (60) that undulates with undulations perpendicular to the first direction, and the other of the first and second retaining portions comprises a retaining channel (80) having side walls that define a channel of complementary shape to that of the undulating protrusion. This arrangement enables an individual to readily store a number of discrete sections or chapters within a single binder assembly, and to subsequently remove and/or replace individual sections as required.

Description

A BINDER ASSEMBLY

The present invention relates to a binder assembly for retaining a plurality of pages, and in particular to a binder assembly for retaining in a releasable manner a number of separate "sections" or "chapters", each section or chapter containing one or more pages.

There are a number of known devices for binding together a plurality of pages. For example, UK patent GB-B-2, 123,341 discloses an elongate binder member having a rigid spine and providing a channel in which are releasably received respective edge portions of a first and second cover, and, between the covers, various pages. Typically, the covers and pages have a number of perforations for receiving lengths of wire which are used to hold the covers and pages together. Then, the channel portion of the binder is slid longitudinally over the edge portions of the covers and pages. The particular form of binder illustrated in GB-B-2, 123,341 has a "T-section" formation extending from the binder, which serves as a means of locating and suspending the binder and its contents from a suitably shaped support.

UK patent application GB-A-2,103,153 discloses a holder member in which perforated loose pages are mounted on posts within the holder member. The holder member has a projection extending therefrom, and the holder is releasably retained within a casing by engagement of the projection within an aperture provided in the casing. The holder member is resiliently deformable to allow the projection to be disengaged from the aperture in order to enable the holder to be removed from the casing. UK patent GB- A- 1,222,730 also describes a loose leaf binder for retaining perforated loose pages. The binder comprises a profiled support which can be shaped to form a U-shaped channel, and which is arranged to receive a number of binding posts for passing through perforations in the loose leaf pages. The binding post may be moved along the length of the channel provided by the profile support, dependent upon the position of the perforations within the pages. A document cover may be mounted within the profiled support, or alternatively the profiled support may be mounted by rivets or the like within a suitable cover.

Whilst the above described devices enable a plurality of pages to be bound together, they do not enable a number of discrete sections or chapters, each section or chapter containing one or more pages, to be separately bound within a single binder assembly. However, it is becoming more commonplace for publications to be issued in discrete sections or chapters. The purchaser may purchase one section each week, month, etc, and over time collect all of the sections of the publication.

Currently, each section may be provided with perforations, to enable the purchaser to place the separate sections within a suitable file, such as a D-ring lever arch file. Alternatively, wire loops can be attached to the ends of the page sections and the wire loops then slotted on to the posts of a conventional D-ring binder mechanism, thereby holding the pages within the binder without the pages needing to be perforated.

Other ways of enabling sections to be bound separately are as follows. If the pages of a section are stapled together, two or more flexible metal strips attached at one end to a binder spline may be threaded through the staples holding the pages together, with the ends being tucked into a slot in and retained within the stiff cover of the binder.

Alternatively, a binder spline may be provided with metal strips attached at the top and bottom of the binder spline. These metal strips are punched with a row of holes on their inside surfaces. Flexible metal rods are then arranged to be fixed into corresponding holes on the two metal strips, with the rods laying along the gutter of the open pages of the sections, usually in the centre spread, thereby retaining the sections in the binder. A variation on this approach is to use continuous flat plastic loops threaded on to two rigid bars that are fixed to the top and bottom of the binder spline. The page sections are then threaded through these loops and held by them in the binder.

Rather than using metal rods or plastic loops, plastic pegs may be used which can be located in slots provided in plastic strips fixed to the top and bottom of the binder spline. The plastic pegs lie along the inside of the binder spline, and page sections may be placed under corresponding pegs provided on each plastic strip, again usually at the centre spread, to retain the page sections.

The above prior art techniques suffer from the disadvantage that they are either inconvenient to use, bulky, and/or costly to manufacture. Hence, it is an object of the present invention to provide an improved binder assembly which enables a plurality of separate sections to be independently retained within the binder assembly in a releasable manner.

Accordingly, the present invention provides a binder assembly comprising: at least one page holder comprising a page holding portion for holding one or more pages and a first retaining portion for retaining the page holder in a binder element; and a binder element for retaining said at least one page holder, the binder element comprising a plurality of second retaining portions, each second retaining portion being arranged to cooperate with the first retaining portion of one of said page holders to retain that page holder in the binder element; wherein the first and second retaining portions have complimentary interlocking shapes to enable the page holder to be slidably moveable to a retained position in the binder element by relative movement of the first and second retaining portions in a first direction, and removal of the page holder from the binder element in a direction perpendicular to the first direction is resisted, and one of the first and second retaining portions comprises a protrusion that undulates with undulations perpendicular to the first direction, and the other of the first and second retaining portions comprises a retaining channel having side walls that define a channel of complimentary shape to that of the undulating protrusion.

Aspects of the present invention provide a binder assembly which has a binder element for retaining a plurality of discrete sections, such as separate sections or chapters of a publication. Page holders are provided for holding one or more pages, in preferred embodiments a page holder holding an individual section or chapter. Each page holder has a first retaining portion arranged to be received within complimentary second retaining portions provided on the binder element. The first and second retaining portions have complimentary interlocking shapes so that a page holder may be moved into a retained position in the binder element by relative movement of the first and second retaining portions in a first direction. Typically, this will be achieved by sliding one of the retaining portions within the other retaining portion. The first and second retaining portions are shaped such that they interlock to resist removal of the page holder from the binder element in the direction perpendicular to the first direction.

This enables an individual to readily store a number of discrete sections or chapters within a single binder assembly, and to subsequently remove and/or replace individual sections as required.

In preferred embodiments, said first retaining portion comprises a protrusion and said second retaining portion comprises an elongate retaining channel, the retaining channel and protrusion being shaped so as to enable the protrusion to be slidably inserted in to the channel in the first, elongate direction, and to resist removal of the protrusion from the channel in said direction perpendicular to the first direction. In this embodiment, the binder element has a plurality of elongate retaining channels provided therein, the channels being spaced apart from one another, and in preferred embodiments being parallel to one another. Each channel is shaped to receive the first retaining portion of a page holder, the first retaining portion taking the form of a protrusion of complimentary shape to the shape of the channel. By this approach, the binder element can be provided as a single unitary structure of compact form, the number of separate sections retainable by the binder element being determined by the number of channels provided in the binder element, and the separation between the channels defining the thickness of the individual sections which may be retained within the binder assembly.

In an alternative embodiment, the first retaining portion comprises an elongate retaining channel and said second retaining portion comprises a protrusion, the retaining channel and protrusion being shaped so as to enable the protrusion to be slidably inserted in to the channel in the first, elongate direction, and to resist removal of the protrusion from the channel in said direction perpendicular to the first direction. In this alternative structure, the protrusions are provided on the binder element, and channels shaped to receive those protrusions are provided by each page holder. Mechanically, the binder assembly operates in the same manner as that described above.

In preferred embodiments, said protrusion has an undulating surface with undulations perpendicular to the elongate direction, and said retaining channel has side walls defining a channel of complimentary shape to the protrusion. Further, the protrusion and retaining channel preferably have a constant cross-section in a plane perpendicular to the elongate direction. This approach enables the protrusion to be slidably inserted in to the retaining channel, whilst the shape of the protrusion and retaining channel resist removal of the protrusion from the retaining channel in a direction perpendicular to the direction of insertion.

In one preferred embodiment, said elongate retaining channel has two opposing side walls defining the shape of the retaining channel in a plane perpendicular to the elongate direction, each side wall having at least one angular section, and the protrusion having corresponding angular sections such that the shape of the protrusion is complimentary to the shape of the channel. This shape of channel provides a particularly compact way for providing a number of channels within a binder element, which have a suitable shape to resist removal of the page holder from the binder element in the direction perpendicular to the elongate direction.

Preferably, each of the two opposing side walls has two angular sections, whereby the elongate retaining channel has a substantially Z-like cross-section in a plane perpendicular to the elongate direction, the protrusion having a complimentary Z-like cross-section to enable the retaining channel and protrusion to interlock. Alternatively, the protrusion and retaining channel may have a W-like cross-section in the plane perpendicular to the elongate direction. The use of a channel and protrusion having complimentary Z-like or W-like cross-sections has been found to combine the benefits of a compact assembly, with the channel walls and protrusions tessellating with one another, whilst also providing a suitably robust structure to resist removal of the page holder from the binder element in the direction perpendicular to the elongate direction.

However, it will be apparent to those skilled in the art that the above described configuration is not the only suitable configuration. For example, in an alternative embodiment, said elongate channel is shaped in a plane perpendicular to the elongate direction so as to include at least one arcuate section, the protrusion having a complimentary arcuate section to cooperate with the retaining channel. In preferred embodiments, the binder element further comprises a spine element. The spine element may preferably comprise a curved strip of material formed on the opposite side of the binder element to the side that receives the page holders. The spine element may include an area in which a suitable title may be printed, such as the title of the publication retained by the binder. Alternatively, the spine element may be adapted to receive a suitable document cover, such as the covers used for conventional books and files, for protecting the pages held by the at least one page holder. In preferred embodiments, the page holding portion has a substantially U- shaped cross section for receiving edge portions of said one or more pages to be held by the page holder. The pages may be mounted in the U-shaped page holding portion by any known means, such as friction, adhesive, clips, or any other suitable retaining mechanism. Preferably the page holder further comprises a flexible neck portion connecting the page holding portion to the first retaining portion. This enables the page holding portion of the page holder to be flexed with respect to the binder element, as will tend to occur during the turning of pages by a user. Preferably, the flexible neck portion has deviations in its surface to facilitate flexing of the page holder. The pages of the section or chapter to be retained by the page holder may be attached after the section is purchased by the customer. However, alternatively, the page holder may comprise a plurality of pages permanently bound to the page holder. Hence, by this approach, the section or chapter can be provided with a page holder already attached, so that the customer merely has to insert the section in to the binder element.

In preferred embodiments, the binder assembly further comprises a retaining component shaped to close off one end of the retaining channels. This enables a protrusion to be inserted in to the retaining channels until one end of the protrusion abuts the retaining component. A folder for holding pages is also described, the folder comprising a binder assembly in accordance with the present invention. Viewed from a second aspect, the present invention provides a binder element for a binder assembly, comprising: a main body portion having a plurality of second retaining portions for retaining a plurality of page holders arranged to hold one or more pages, each second retaining portion being arranged to cooperate with a first retaining portion provided on a page holder to retain that page holder in the binder element; the second retaining portions being shaped to be complimentary to the first retaining portion and to interlock with the first retaining portion; wherein the page holder is slidably moveable to a retained position in the binder element by relative movement of the first and second retaining portions in a first direction, and removal of the page holder from the binder element in a direction perpendicular to the first direction is resisted, and one of the first and second retaining portions comprises a protrusion that undulates with undulations perpendicular to the first direction, and the other of the first and second retaining portions comprises a retaining channel having side walls that define a channel of complimentary shape to that of the undulating protrusion.

Viewed from a third aspect, the present invention provides a page holder comprising: a page holding portion for holding one or more pages; a first retaining portion for engaging with one of a plurality of second retaining portions provided on a binder element so as to enable the page holder to be retained by the binder element; the first retaining portion being shaped to be complimentary to the second retaining portions and to interlock with one of said second retaining portions; wherein the page holder is slidably moveable to a retained position in the binder element by relative movement of the first and second retaining portions in a first direction, and removal of the page holder from the binder element in a direction perpendicular to the first direction is resisted, and one of the first and second retaining portions comprises a protrusion that undulates with undulations perpendicular to the first direction, and the other of the first and second retaining portions comprises a retaining channel having side walls that define a channel of complimentary shape to that of the undulating protrusion. The present invention will be described further, by way of example only, with reference to preferred embodiments thereof as illustrated in the accompanying drawings, in which:

Figures 1A and IB illustrate a binder assembly according to the invention;

Figures 2A and 2B show details of the binder assembly of Figures 1A and IB;

Figure 3 illustrates a binder element according to the invention; Figure 4 shows details of the binder element of Figure 3;

Figure 5 illustrates a page holder according to the invention;

Figure 6 shows details of the page holder of Figure 5;

Figure 7 is an isometric view of the binder assembly of the invention when inserted within a cover. Figures 8 and 9 illustrate components used to locate the page holders in the binder assembly;

Figure 10 illustrates other binder assemblies.

Figure 1A illustrates a binder assembly, and Figure 1A provides a cross- sectional view of the binder assembly. The binder assembly comprises a binder element 10, and one or more page holders 20, each page holder 20 having a protrusion arranged to be received in a corresponding channel within the binder element 10.

Figure 2A provides a more detailed illustration of the page holders 20, and of the channels provided within the binder element 10. In preferred embodiments, the page holder 20 has a U-shaped page holding portion 50 for receiving one or more pages. A protrusion 60 depends from the page holding portion 50, and in preferred embodiments, is connected to the page holding portion via a flexible neck portion 70.

The pages may be attached to the page holding portion 50 using any suitable technique. For example, the walls of the U-shaped page holding portion may be resiliently biased towards one another, such that pages inserted between the two walls are retained between the two walls by friction. However, as will be appreciated by those skilled in the art, any other suitable means for mounting the pages within the U- shaped page holding portion can be employed, such as by use of adhesive, or mechanical means such as clips. The pages of the section or chapter to be retained by the page holder may be attached after the section is purchased by the customer.

However, alternatively, the section or chapter can be provided with a page holder already attached, so that the customer merely has to insert the section in to the binder element.

The binder element 10 preferably has an elongate structure, the elongate direction being into the page when viewing Figure 2 A. The binder element 10 has elongate retaining channels 80 defined therein, the channels being spaced apart from one another, and extending through the binder element 10 in the elongate direction. The protrusion 60 has a complimentary interlocking shape to that of the channel 80, thereby enabling the protrusion 60 to be inserted into the retaining channel 80 in the elongate direction. Preferably, the protrusion 60 takes the form of a single elongate protrusion of the same or similar length to the length of the retaining channels 80. However, alternatively, a plurality of shorter length protrusions could be formed depending from the page holding portion 50 of the page holder 20.

In the embodiment illustrated in Figure 2A, each elongate retaining channel 80 has two opposing side walls defining the shape of the retaining channel in a plane perpendicular to the elongate direction, and each side wall has two angular sections 90, 100, 110, 120 such that the elongate retaining channel has a substantially Z-like cross-section in the plane perpendicular to the elongate direction. As illustrated in Figure 2A, the protrusion has a complimentary Z-like cross-section to enable the retaining channel and protrusion to interlock. This design has been found to combine the benefits of a compact assembly, with the channel walls and protrusions tessellating with one another, whilst also providing a suitably robust structure to resist removal of the page holder from the binder element in the direction perpendicular to the elongate direction. However, it will be appreciated by those skilled in the art that there is no requirement for the protrusion and the retaining channels to have the particular shape illustrated in Figure 2A. All that is required is for the retaining channels and protrusions to have complimentary interlocking shapes which enable the protrusions to be inserted into the channels in the elongate direction, whilst the shapes are such as to resist removal of the page holder from the binder element in the direction perpendicular to the elongate direction. The flexible neck portion 70 is provided to enable the page holding portion 50 to be flexed with respect to the protrusion 60, this facilitating the turning of pages by a user. As illustrated in Figure 2A, in preferred embodiments the flexible neck portion has deviations in its surface to facilitate flexing of the page holder. However, figure 2B illustrates an alternative embodiment in which neck portion 70 has a reduced thickness portion in order to provide the desired flexibility. Preferably, both the binder element 10 and the page holders 20 are formed of plastic material, for example rigid PVC, by extrusion moulding. The arrangement illustrated in Figure 2A can be readily manufactured by extrusion moulding, whilst the use of plastic materials provides the assembly with sufficient flexibility characteristics to enable the sections or chapters to be turned with respect to one another. In preferred embodiments, the main body of the binder element 10 in which the retaining channels are formed has a back surface 100 which has an undulating shape to maintain a consistent wall thickness, this helping to reduce distortion during manufacture.

As illustrated in Figure 1A, the binder element 10 may, in preferred embodiments, have a spine element 30 formed therein. The spine element 30 may be a unitary structure as illustrated in Figure 1A, or alternatively may take the form of two spine elements 40 separated by a small gap, as illustrated in Figure IB, the provision of this gap reducing costs for tooling and manufacture.

Figure 3 illustrates the binder element 10 without any page holders 20 retained in the binder element 10. As illustrated in Figure 3, the binder element 10 has a plurality of retaining channels 80 spaced apart from one another and extending in the elongate direction. As is apparent from Figure 3, the binder element can be formed as a unitary structure, and hence is suitable for manufacture by an extrusion process.

Figure 4 provides a more detailed illustration of the binder element of Figure

3, and includes some exemplary dimensions, expressed in millimetres, which may be used to produce a binder element 10 in accordance with the first embodiment of the present invention. It should be noted that these dimensions are provided purely for the purpose of illustration, and it will be apparent to those skilled in the art that the dimensions of the binder element can be chosen at will by the designer, dependent on a number of factors, such as the size of the sections to be retained within the binder element.

Figure 5 is an illustration of a page holder in accordance with preferred embodiments of the present invention. As discussed earlier, the page holder preferably has a U-shaped page holding portion 50, a flexible neck portion 70, and a protrusion 60 connected to the U-shaped page holding portion 50 via the flexible neck portion 70. Figure 6 provides a more detailed illustration of the page holder of Figure 5, and includes some exemplary dimensions, expressed in millimetres, which may be used to manufacture a page holder in accordance with the first embodiment of the present invention. As with Figure 4, it will be appreciated by those skilled in the art that the dimensions are provided purely for the sake of illustration, and may readily be varied by the designer.

Figure 7 provides an isometric view of a binder assembly in accordance with the first embodiment of the present invention. As illustrated in Figure 7, a document cover 110 may be attached to the spine element 40 of the binder assembly. However, it will be appreciated by those skilled in the art that there is no requirement for a document cover 110 to be attached to the binder assembly. In particular, if each of the sections mounted in a page holder has a suitable protective cover, then the binder assembly, including the individually retained sections, can be freestanding. If a single spine element 30 is provided as illustrated in Figure 1 A, then that spine element may include an area in which suitable title may be printed, such as the title of the publication retained by the binder. Such a freestanding binder assembly may be mounted on a stand if desired.

However, returning to the embodiment illustrated in Figure 7, it is apparent that the binder assembly may be neatly mounted within a document cover 110, and that page holders 20 can then readily be slidably inserted into the binder element 10 in the elongate direction. As new sections are published, these can readily be added to the binder assembly, until all of the available retaining channels in the binder assembly have been used. Further, when sections are replaced or updated, the old section can be removed, and the updated section inserted in its place.

Preferably, the binder element and/or the page holders include a mechanism to locate the page holder in a retained position within the binder element 10. In one embodiment, this may be achieved by having one end of the retaining channels 80 closed off by an integral component, or by a separate component (such as a lip provided on the document cover 110), so that a page holder 20 can be inserted into the channel 80 until one end of the page holder abuts the closed end of the retaining channel 80. Figures 8 and 9 illustrate two preferred embodiments of components that may be used to close off one end of the retaining channels 80. Figure 8C illustrates the basic shape of a suitable component 200 when viewed from the under side. Figure 8B shows the component 200 from a front elevation, and as can be seen, the component is preferably manufactured to be thin. In preferred embodiments, this thin component 200 is glued into place on the base of the binder element 10, as illustrated in Figure 8A, which is a plan view of the binder assembly with the component 200 attached to the underside. This enables the protrusions 60 provided on the page holders 20 to be inserted into the top of the retaining channels 80 and to be slid down the retaining channels 80 until the protrusions 60 abut the surface of the retaining component 200.

Figure 9 illustrates an alternative embodiment of a retaining component, which may be manufactured by injection moulding. Figure 9 A shows a plan view of the component 210, which has a thin base element 240 of the same or similar shape to the retaining component 200. Upstanding from the base element 240 are a number of locating ridges 220, these locating ridges 220 being illustrated more clearly in Figure 9B, which provides a front elevation view of the retaining component 210. At the upper part of the retaining ridges 220, a thin wall 230 is provided to help maintain rigidity of the component 210. The binder assembly is located on the retaining element 210, such that the ridges 220 pass between the main body portion of the binder element 10 and the spine element 30, 40, the ridges cooperating with the surface 100 of the binder element. To retain the component 210 more securely on the binder assembly, glue may also be used. Figure 9C provides a view of the underside of the binder assembly when the component 210 is in place, and all of the page holders are located in the channels of the binder element 10. Further, Figure 9D illustrates a side elevation of the component 210, in which a contoured surface 250 (for example comprising a series of 'barbs') on the ridges 220 can be seen. This surface aids to hold the ridges 220 against the surface 100 of the binder element 10.

Although figures 8 and 9 illustrate components that may be provided to locate the page holders within the retaining channels 80, it will be apparent to those skilled in the art that alternative techniques may be used. For example, it is possible to provide a notch in the retaining channel 80, and a corresponding recess within the protrusion 60 of the page holder 20. The page holder may then be inserted into the retaining channel until the notch locates in the recess. Clearly, the notch and recess may be reversed, such that the recess is in the retaining channel 80 and the notch is provided on the protrusion 60. A second embodiment of the invention will now be discussed with reference to Figure 10. As illustrated in Figure 10 A, the protrusions 62 of the second embodiment have a substantially V-shaped cross section, and locate in complimentary V-shaped channels in a binder assembly 12. As in the first embodiment, each page holder 20 has a U-shaped page holding portion 50 connected to the protrusion 62 via a flexible neck portion 70. As illustrated in Figure 10A, the sections or chapters 300 may comprise a number of loose leaf pages which are retained within the page holding portions 50 by a glue binding 310. Figure 10B provides a perspective view of the second embodiment, in which the elongate dimension of both the page holders and the retaining channels can be more readily seen. Although particular embodiments of the present invention have been described herein, it will be appreciated that the invention is not limited thereto, and that many modifications and additions thereto may be made within the scope of the invention.

Claims

1. A binder assembly comprising: at least one page holder comprising a page holding portion for holding one or more pages and a first retaining portion for retaining the page holder in a binder element; and a binder element for retaining said at least one page holder, the binder element comprising a plurality of second retaining portions, each second retaining portion being arranged to cooperate with the first retaining portion of one of said page holders to retain that page holder in the binder element; wherein the first and second retaining portions have complimentary interlocking shapes to enable the page holder to be slidably moveable to a retained position in the binder element by relative movement of the first and second retaining portions in a first direction, and removal of the page holder from the binder element in a direction perpendicular to the first direction is resisted, and one of the first and second retaining portions comprises a protrusion that undulates with undulations perpendicular to the first direction, and the other of the first and second retaining portions comprises a retaining channel having side walls that define a channel of complimentary shape to that of the undulating protrusion.

2. A binder assembly according to Claim 1, wherein said first retaining portion comprises the protrusion and said second retaining portion comprises the retaining channel.

3. A binder assembly according to Claim 1, wherein said first retaining portion comprises the retaining channel and said second retaining portion comprises the protrusion.

4. A binder assembly according to Claim 1 and Claim 2, wherein walls of the binder element between respective channels have substantially the same shape as the channel.

5. A binder assembly according to any preceding claim, wherein the protrusions and channels tessellate with one another.

6. A binder assembly according to any preceding claim, wherein the protrusion and retaining channel have a constant cross-section in a plane perpendicular to the elongate direction.

7. A binder assembly according to any preceding claims, wherein the retaining channel has two opposing side walls defining the shape of the retaining channel in a plane perpendicular to the first direction, each side wall having at least one angular section, and the protrusion having corresponding angular sections such that the shape of the protrusion is complimentary to the shape of the channel.

8. A binder assembly according to any preceding claim, wherein each of the two opposing side walls has two angular sections, whereby the retaining channel has a substantially Z-like cross-section in a plane perpendicular to the first direction, the protrusion having a complimentary Z-like cross-section to enable the retaining channel and protrusion to interlock.

9. A binder assembly according to any of claims 1 to 6, wherein said channel is shaped in a plane perpendicular to the first direction so as to include at least one arcuate section, the protrusion having a complimentary arcuate section to cooperate with the retaining channel.

10. A binder assembly according to any preceding claim, wherein the binder element further comprises a spine element.

11. A binder assembly according to Claim 10, wherein the spine element is adapted to receive a document cover for protecting the pages held by the at least one page holder.

12. A binder assembly according to any preceding claim, wherein the page holding portion has a substantially U-shaped cross section for receiving edge portions of said one or more pages to be held by said page holder.

13. A binder assembly according to any preceding claim, wherein the page holder further comprises a flexible neck portion connecting the page holding portion to the first retaining portion.

14. A binder assembly according to Claim 13, wherein the flexible neck portion has deviations in its surface to facilitate flexing of the page holder.

15. A binder assembly according to any preceding claim, wherein the page holder comprises a plurality of pages permanently bound to the page holder.

16. A binder assembly according to any preceding claims, comprising a retaining component shaped to close off one end of the retaining channels.

17. A folder for holding pages, comprising a binder assembly according to any preceding claim.

18. A binder element for a binder assembly, comprising: a main body portion having a plurality of second retaining portions for retaining a plurality of page holders arranged to hold one or more pages, each second retaining portion being arranged to cooperate with a first retaining portion provided on a page holder to retain that page holder in the binder element; the second retaining portions being shaped to be complimentary to the first retaining portion and to interlock with the first retaining portion; wherein the page holder is slidably moveable to a retained position in the binder element by relative movement of the first and second retaining portions in a first direction, and removal of the page holder from the binder element in a direction perpendicular to the first direction is resisted, and one of the first and second retaining portions comprises a protrusion that undulates with undulations perpendicular to the first direction, and the other of the first and second retaining portions comprises a retaining channel having side walls that define a channel of complimentary shape to that of the undulating protrusion.

19. A binder element according to Claim 18, wherein said second retaining portion comprises the retaining channel, and the first retaining portion comprises a protrusion.

20. A binder element according to Claim 18 or 19, wherein a binder assembly according to any preceding claim, wherein each of the two opposing side walls has two angular sections, whereby the retaining channel has a substantially Z-like cross- section in a plane perpendicular to the first direction, the protrusion having a complimentary Z-like cross-section to enable the retaining channel and protrusion to interlock.

21. A binder element according to any of Claims 18 to 20, wherein the retaining channel has a constant cross-section in a plane perpendicular to the first direction.

22. A binder element according to any of Claims 18 to 21, comprising a retaining component shaped to close off one end of the retaining channels.

23. A page holder comprising: a page holding portion for holding one or more pages; a first retaining portion for engaging with one of a plurality of second retaining portions provided on a binder element so as to enable the page holder to be retained by the binder element; the first retaining portion being shaped to be complimentary to the second retaining portions and to interlock with one of said second retaining portions; wherein the page holder is slidably moveable to a retained position in the binder element by relative movement of the first and second retaining portions in a first direction, and removal of the page holder from the binder element in a direction perpendicular to the first direction is resisted, and one of the first and second retaining portions comprises a protrusion that undulates with undulations perpendicular to the first direction, and the other of the first and second retaining portions comprises a retaining channel having side walls that define a channel of complimentary shape to that of the undulating protrusion.

24. A page holder according to Claim 23, wherein said first retaining portion comprises the protrusion, and the second retaining portion comprises the channel.

25. A page holder according to Claim 23 or 24, wherein each of the two opposing side walls has two angular sections, whereby the retaining channel has a substantially Z-like cross-section in a plane perpendicular to the first direction, the protrusion having a complimentary Z-like cross-section to enable the retaining channel and protrusion to interlock.

26. A page holder according to any of Claims 23 to 25, wherein the protrusion has a constant cross-section in a plane perpendicular to the first direction.

27. A page holder according to any of claims 23 to 26, comprising a plurality of pages permanently bound to the page holder.