Tube

Abstract

 A paper or board tube (10) cut along its length and having a hinge along its length opposite the cut so that it can be opened by moving the edges of the division apart and closed by moving them together is disclosed. The hinge is a slit (26) in the inner surface of the tube (10) or a slot (16) in the outer surface. The tube (10) is useful as a protective container for articles; it can easily be opened, placed around the article, and closed. The tube (10) is also useful as a winding core for filaments such as wires and sheet material such as paper, textiles and plastics films; the empty tube (10) can be opened, slipped over an upright former and closed around the former. The tubes nest better than separate tube halves, making storage and transport more efficient.

Description

[0001] The invention relates to a tube. It finds particular application in tubes of helically (or 'spirally') wound board.

[0002] The use of tubes, usually of circular cross section, as containers is commonplace. Often an item to be contained in a tube cannot be slid inside the tube; in this case, the tube is cut in half longitudinally to give two semicircular portions which are placed on either side of the item, closed up and secured together.

[0003] The cutting is usually performed by the tube manufacturer. Known cutting methods often result in the tube being cut into two non-identical halves. Thus, either the cut halves must be kept together throughout storage and transport, or a poor fit around the item must be accepted. A further problem with this system is that the half tubes cannot be efficiently stacked, making storage and transport costs relatively high.

[0004] Tubes are also used as winding cores for, for example, filaments such as wires and sheet material such as paper, textiles and plastics films. In some applications, the empty tube is slipped over an upright former, where the material is wound onto it, in which case it must be raised above the former.

[0005] The present invention provides a tube which hinges open so that it can be placed around an item, such as a former or an item to be packaged, and then closed up and secured.

[0006] According to the invention there is provided a tube divided along its lengthy and a hinge along its length so that it can be opened by moving the edges of the division apart and closed by moving them together, characterised in that the hinge is a region of the tube thinner than the tube adjacent the hinge.

[0007] The tube is preferably divided by a longitudinal cut.

[0008] Preferably, the tube is of circular cross section.

[0009] Preferably, the hinge is generally diametrically opposite the cut, but need not be. There may be two or more hinges.

[0010] Preferably, the tube is a helically wound tube of board. More preferably, it is formed of at least two plies.

[0011] The hinge may be a slit in the inner surface of the tube or it may be a channel in the outer surface. In the case of multi-ply board tubes, it is preferable that one of the plies at least is of a strong board, such as kraft. The slit or channel in the tube wall can then be in the relatively weaker ply or plies, leaving the stronger ply to give adequate strength. The stronger ply should give sufficient strength to the tube for its intended application, and should also provide a sufficiently strong hinge.

[0012] The invention will be further described by way of example with reference to the drawings in which:

Figure 1 shows a diagrammatical schematic view of a tube according to a first embodiment of the invention, open;

Figure 2 shows in more detail an end plan view of the tube of Figure 1, nearly closed; and

Figure 3 shows an end plan view of a tube according to a second embodiment of the invention.

[0013] The tube 10 of the drawings is a helically wound 2-ply board tube. The inner ply 12 is of kraft paper and the outer ply 14 is of recycled board; this is seen in Figure 2. The tube has been cut along its length; diametrically opposite the cut, a channel 16 is cut in the outer surface of the tube, through the outer ply 14, to form two semicircular half tubes 10a,10b. The inner ply 12 of kraft paper remains intact, keeping the two half tubes 10a,10b together and providing a hinge along the line of channel 16.

[0014] The intact tube is made in a conventional manner. The tube is then cut by a single longitudinal through cut. The channel 16 is formed by making two cuts in or through the outer ply 14 of recycled board stopping short of the inner ply 12 of kraft paper. The portion of the outer ply 14 between the two cuts is removed from the channel 16.

[0015] The size and shape of the channel 16 are chosen to allow the opening between the two half tubes 10a,10b to be great enough for the intended application. Preferably, the channel width is at least 1.15d, where d is the depth of the channel 16; this will enable the opening between the half tubes 10a,10b to be at least equal to the diameter of the closed tube 10, so that it can be placed around anything which will fit inside the closed tube 10.

[0016] The channel 16 should not be made any wider than is necessary to allow the required opening of the tube halves 10a,10b, to minimise the weakening of the tube caused by the channel.

[0017] In use, the tube 10 is opened by moving the cut edges of the tube halves apart. The open tube is placed around the item and the half tubes 10a,10b are closed by bringing the cut edges of the tube halves together, and securing them together.

[0018] Figure 3 shows a second embodiment of the invention. The tube 20 is a helically wound 2-ply board tube. The inner ply 22 is of recycled board and the outer ply 24 of kraft paper. The tube is cut along its length to form two semicircular tube halves 20a,20b. Diametrically opposite the cut, the inner wall of the tube is slit through the inner ply 22 of recycled board, but not through the outer ply 24 of kraft paper. The kraft paper ply 24 is strong enough to hold the two tube halves 20a,20b together and to provide a hinge between the tube halves.

[0019] The tube 20 can be opened in the same way as the tube shown in Figures 1 and 2, the slit in the inner wall of the tube opening to a generally V-shaped channel 26. The outer ply 24 deforms sufficiently to accommodate this movement.

[0020] Tubes 20 according to the second embodiment of the invention are used in the same way as the tubes 10 shown in Figures 1 and 2.

[0021] Tubes according to the invention are useful as winding cores. The tube is opened as already described and placed around a former. This avoids the need for the winding core to be placed on the former from one end. This is particularly useful in the case of an upright former, since the need to raise the winding core above the upper, free, end of the former is avoided.

[0022] The ply or plies of the tubes of the invention which are not cut or scored will normally be of a stronger material than those which are.

[0023] Since the halves of the tubes of the invention are never completely separated, they always match, giving better protection to the contained item and a better appearance.

[0024] Tubes according to the invention nest better than separate tube halves, making storage and transport more efficient.

Claims

1. A tube (10) (20) divided along its length and a hinge (16) (26) along its length so that it can be opened by moving the edges of the division apart and closed by moving them together, characterised in that the hinge (16) (26) is a region of the tube thinner than the tube adjacent the hinge (16).

2. A tube (10) (20) according to claim 1, one circumferential face (12) (24) of which is continuous between the edges of the division.

3. A tube (10) (20) according to claim 1 or 2, one circumferential face (12)(24) of which is continuous across the hinge (16)(26).

4. A tube (10) (20) according to any of claims 1 to 3 the portion of which (10a)(20a) on one side of the hinge (16)(26) being integral with the portion (10b) (20b) on the other side.

5. A tube (10) (20) according to any preceding claim of paper or board.

6. A tube (10) (20) according to claim 5 in which the board is helically wound.

7. A tube (10) (20) according to claim 5 or 6 comprising at least two plies (12,14) (22,24)

8. A tube (10) according to any preceding claim in which the hinge (16) is a channel in the outer surface of the tube.

9. A tube (10) according to claim 7 and 8 in which the inner ply (12) is of a relatively strong paper or board such as kraft paper.

10. A tube (10) according to claim 8 or 9 in which the width of the channel (16)is at least 1.15d, where d is the depth of the channel.

11. A tube (10) according to claim 10 in which the width of the channel (16) is approximately 1.15d.

12. A tube (20) according to any of claims 1 to 7 in which the hinge (26) is a slit in the inner surface of the tube.

13. A tube (20) according to claim 7 and 12 in which a ply (24) of relatively strong paper or board such as kraft paper is not slit.

14. A tube (10) (20) according to any preceding claim in which the hinge (16)(26) is generally opposite the division.

15. A tube (10)(20) according to any preceding claim of generally circular cross section.

16. A tube substantially as described with reference to Figures 1 and 2 of the drawings.

17. A tube substantially as described with reference to Figure 3 of the drawings.

Drawing