This invention relates to a rod for a hanging file folder, and a hanging file folder with at least one such rod.

A hanging file holder (also called "hanging folder" or "hanging file") is a kind of folder for holding loose papers together for organization and protection. Such a hanging file folder includes two rods and a sheet of paper, plastic, or other thin, but stiff, material which is folded in half. Each of the rods is fixed to a respective longitudinal side of the sheet of paper, plastic, or such like thin but stiff material so that when the file folder is folded, the two rods are side by side with and parallel to each other. Each of the rods has two end-hooks. When in use, the hanging file folder is folded such that the two rods are parallel to each other, and the end-hooks of the rods are supported by a pair of parallel rails of a filing cabinet or filing box. The space between the two folded halves of the sheet of paper, plastic, or such like thin but stiff material may thus hold various items for organization and protection purposes.

The strength of the hanging file folder depends partly on the strength of the rods. For relatively heavy-duty hanging file folders, the rods are made of a metal or metal alloy, e.g. stainless steel, although plastic materials may also be used for manufacturing rods for less heavy-duty hanging file folders. Given the rise in the cost of metals, metal alloys, plastics materials and environmental concern, it is an object of the present invention to provide a rod for a hanging file folder, and a hanging file folder with at least one such rod, which may be made of less metal, metal alloy, or plastic materials without jeopardizing the strength of the rod and the resultant hanging file folder, or at least to provide a useful alternative to the trade and public.

According to a first aspect of the present invention, there is provided a rod for a hanging file folder, including a body with two opposite lateral sides and two opposite longitudinal ends, and a hook at each of said two longitudinal ends of said body; characterized in that at least a part of each of said two lateral sides undulate.

According to a second aspect of the present invention, there is provided a hanging file folder including at least a sheet of foldable material with two longitudinal sides, and at least a rod fixedly engaged with one of said longitudinal sides, said rod including a body with two opposite lateral sides and two opposite longitudinal ends, and a hook at each of said two longitudinal ends of said body; characterized in that at least a part of each of said two lateral sides undulate.

Embodiments of a rod for a hanging file folder and a hanging file folder with rods according to the present invention will now be described, by way of examples only, with reference to the accompanying drawings, in which:

Fig. 1 is a front view of a rod for a hanging file folder according to an embodiment of the present invention;

Fig. 2 is an enlarged sectional view taken along the line A-A of Fig. 1;

Fig. 3 is a front perspective view of the rod shown in Fig. 1;

Fig. 4 is a rear perspective view of the rod shown in Fig. 1;

Fig. 5 shows the rod of Fig. 1 fixedly engaged with a sheet of foldable material to form a hanging file folder according to an embodiment of the present invention;

Fig. 6 shows four prior art rods for a hanging file folder arranged side by side with each other;

Fig. 7 shows three rods according to the present invention arranged side by side with each other; Fig. 8 shows a prior art hanging file folder and a hanging file folder according to the present invention installed in a filing box;

Fig. 9 shows the prior art hanging file folder and hanging file folder according to the present invention shown in Fig. 8, each holding an iron plate; and

Fig. 10 shows the prior art hanging file folder and hanging file folder according to the present invention shown in Fig. 8, each holding sheets of paper.

A rod for a hanging file folder according to an embodiment of the present invention is shown in Figs. 1 to 4, and generally designated as 10. The rod 10 may be made of a metal, a metal alloy, a plastic material, or a combination thereof. The rod 10 has an elongate body 12 with opposite first and second major surfaces 14, 16. At each of two longitudinal ends of the body 12 is a hook 18.

It can be seen that the body 12 has a pair of opposite lateral sides 20, 22 which undulate in phase with each other along nearly the whole length of the body 12. Crests 50 along the side 20 and troughs 52 along the side 22 are straight, and so are slopes 54 adjoining adjacent crests and troughs 52.

As shown more clearly in Fig. 2, a continuous ridge 24 is formed on and runs along the first major surface 14. The ridge 24 curves out of the first major surface 14 of the body 12 and undulates parallel to and in phase with the lateral sides 20, 22. A continuous trough 26 is formed on and runs along the second major surface 16 of the body 12. The trough 26 undulates parallel to and in phase with the lateral sides 20, 22, and the trough 26 has a triangular cross section.

Fig. 5 shows a hanging file folder 32 formed of a sheet of foldable material 30 and two rods 10. The sheet 30 may be made of such foldable material as paper, plastic, and such like thin but stiff material, and is folded in half about a line 34 which is parallel to two opposite longitudinal sides 28. When the sheet 30 is so folded, the two longitudinal sides 28 are side by side with and parallel to each other. To each longitudinal side 28 is fixedly engaged a rod 10. Adjacent and along each longitudinal side 28 are formed a number of "teardrop" slots 36 for releasable engagement with indexing tabs (not shown).

Fig. 6 shows four conventional rods 10a arranged side by side with each other, and Fig.

7 shows three rods 10 according to the present invention arranged side by side with each other. It can be seen that, as shown in Fig. 6, the distance D between the two lateral sides of each conventional rod 10a is equal to the width P of the rod 10a. However, in the case of the rod 10 according to the present invention, and as shown in Fig. 7, the distance D' between the two lateral sides 20, 22 of the rod 10 is larger than the width P' of the rod 10. Thus, if we arrange D' to be equal to D, P' will be smaller than P. This means that less material is required for forming the rod 10 in which the distance D' between its two lateral sides 20, 22 is the same as the distance D between the two lateral sides of the conventional rod 10a.

Experiments were carried out to test the strength of the rods 10 according to the present invention as compared with the prior art rods 10a. Fig. 8 shows a filing box 38 with a pair of parallel rails 40 (of which only one is shown) supporting the hanging file folder 32 with two rods 10 according to the present invention and a prior art hanging file folder 32a with two prior art rods 10a. Both hanging file folders 32, 32a are shown in Fig. 8 in their natural state with no loading.

As shown in Fig. 9, into the space of each of the hanging file folders 32, 32a is placed an iron plate 42 of 3 kg. It was found that the mouth of the hanging file folder 32 is open by up to about 2.54 cm, whereas the mouth of the prior art hanging file folder 32a is open by up to about 5.08 cm.

As shown in Fig. 10, into the space of each of the hanging file folders 32, 32a is placed a bundle of A4 paper 44 of a thickness of 28 mm and a weight of around 1.36 kg. It was found that there was no observable deformation of the rods 10 according to the present invention, whereas the prior art rods 10a are obviously deformed. It can thus be seen that even if the rod 10 according to the present invention is made with less material, it is stronger than the prior art rod 10a.

It should be understood that the above only illustrates an example whereby the present invention may be carried out, and that various modifications and/or alterations may be made thereto without departing from the spirit of the invention. For example, although the rod 10 discussed above has one continuous ridge 24 running along its first major surface 14, it is possible to provide instead a number of disjointed ridge sections along the first major surface 14. Similarly, although the rod 10 discussed above has one continuous trough 26 running along its second major surface 16, it is possible to provide instead a number of disjointed trough sections along the second major surface 16. In addition, although in the rod 10 discussed above, the crests 50, troughs 52 and slopes 54 are straight, it is envisaged that they each of them may be curved.

It should also be understood that various features of the invention which are, for brevity, described here in the context of a single embodiment, may be provided separately or in any appropriate sub-combinations.