The present invention concerns a conveying wire with disc-shaped conveying members for use in an endless tube conveyor system, the conveying wire consisting either of a number of twisted strands or of a number of plaited strands, each are made of thin threads or fibres of synthetic plastic, the conveying wire including an outer jacket at least between the conveying members which are fastened directly to the conveying wire by injection moulding, The invention also concerns a method for making a conveying wire according to the invention.

Background of the Invention

EP-Al-0 659 661 describes a conveying cable made of polyester fibres, and which is intended for use for transporting material in tube conveying systems, where disc- shaped conveying members of polyurethane by injection moulding are fastened directly on an outer sheath which also consists of polyurethane, which should ensure a permanent connection between the various components.

DK/EP 07671 16 T3 discloses a conveying wire of a tube scraping conveyor, preferably for feeding installations in stables, consisting of a steel wire and with carriers provided thereon with relatively narrow spacing, forming an injection- moulding-like bond to the steel wire, and with a moulded wire sheathing, where the conveying wire is peculiar in that the carriers are of a relatively stiff plastic moulded with lateral, short thin cover extensions over the steel wire, while the sheathing is a separate elastic plastic moulded between neighbouring carriers over the steel wire as well as over at least an outer part of the cover extensions such that the wire sheathing is tightly bonded to the cover extensions.

US 2002/0033270 Al discloses a disc cable capable of preventing occurrence of fine pieces of a metal wire material caused by wear and damage of a metal wire and preventing mixing of the fine pieces into feed is provided. A cover layer formed of synthetic resin is formed on the surface of the metal wire, and a groove-like part to which the surface of the metal wire is exposed is formed not forming a part of the cover layer in a predetermined spacing relation in a longitudinal direction of a cable. Then a disc formed of synthetic resin is moulded, and the synthetic resin is flown into the groove-like part to form a protrusion on the disc to fixedly mount it on the cable to produce a disc cable having the discs disposed in a predetermined spacing relation on the cable.

Object of the Invention

On that background, it is the purpose of the invention to provide an improved transport wire of the kind mentioned in the introduction, and which in a simple way enables achieving an extraordinarily good, permanent attachment of the outer jacket on the conveying wire and a direct connection between the outer jacket and the conveying wire, and at the same time an extraordinarily good adhesion between the conveying wire and the disc-shaped conveying members.

Description of the Invention

The conveying wire according to the invention is peculiar in that the sections of the outer jacket have been connected directly with the conveying wire by injection moulding, and that opposing end parts of the sections of the outer jacket extend in under or in over opposing end parts of the disc-shaped conveying members.

In a simple way it is hereby possible to achieve a completely extraordinary, good, permanent attachment of the outer jacket directly on the conveying wire, and a direct permanent connection between the outer jacket and the conveying wire and the discshaped conveying members.

The primary object of coating the fibre wire is to protect it against ingression of e.g. hard particulate minerals that otherwise would damage the fibre wire and eventually cause breakage. However, it is also important to protect the fibre wire which becomes more open in the surface over time due to loose fibres. This may enable dust, together with moisture, to bind on the surface, which after some time may be the cause of mould formation. In other words, it is an important secondary object of the outer jacket to ensure a substantially improved hygiene. The fact that the outer jacket is fastened by injection moulding directly to the conveying wire at a very high pressure provides a more optimal attachment between the outer jacket and the conveying wire.

In addition, at the same time there is achieved possibility of choosing specific and more flexible plastic materials which can "cooperate". With the aim of ensuring an optimal connection between the outer jacket and the discshaped conveying members, it may be additionally advantageous that the conveying wire according to the invention is designed such that that opposing end parts of the sections of the outer jacket are designed with an annular bead or thickening. The conveying wire according to the invention is suitably designed such that the sections of the outer jacket, which are fastened to the conveying wire with mutual spacing by injection moulding, consist of a soft thermoplastic elastomer, for example Santoprene™. With the object of further optimising the connection between the outer jacket and the conveying wire it may be advantageous with a design such that the annular bead or thickening of opposing end parts of the sections is disposed internally of the opposing end parts of the disc-shaped conveying members, which are subsequently fastened directly to the conveying wire.

The conveying wire according to the invention can be designed such that its basic wiring consists of a fibre wire with a number of twisted strands or a plaited fibre wire.

An alternative embodiment of the conveying wire according to the invention is designed such that at the outermost end part of the end parts, the conveying members consist of the same soft material as the outer jacket in that the outermost end parts are injection moulded together with the outer jacket before injection moulding of the conveying members. The invention also concerns a method for making a conveying wire according to the invention, wherein a fibre wire with a number of twisted strands or a plaited fibre wire is provided with mutually spaced, disc-shaped conveying members by injection moulding and with outer jacket parts there between, the method being peculiar by the following method steps in sequence:

- keeping the fibre wire tight during unwinding, and keeping the conveying wire tight during winding;

- injection moulding of outer jacket parts directly on the fibre wire with mutual spacing;

- injection moulding of disc-shaped conveying members directly on the fibre wire between the outer jacket parts.

Alternatively, the method for making a conveying wire according to the invention, wherein a fibre wire with a number of twisted strands or a plaited fibre wire is provided with mutually spaced, disc-shaped conveying members by injection moulding and with outer jacket parts there between, may be peculiar by the following method steps in sequence:

- keeping the fibre wire tight during unwinding, and keeping the conveying wire tight during winding;

- injection moulding of disc-shaped conveying members directly on the fibre wire with mutual spacing.

In other words, the method according to the invention can be varied with regard to the sequence of injection moulding of the disc-shaped conveying members and the outer jacket parts, respectively, directly on the fibre wire, which in both cases, as an essential feature, is kept suitably tight during the injection moulding such that the strands of the fibre wire do not open during the injection moulding.

Description of the Drawing

The invention is explained in more detail in the following with reference to the drawing in which:

Fig. 1 shows a plan view of an alternative embodiment of a conveying wire according to the invention with a number of disc-shaped conveying members; Fig. 2 shows a plan view, partly in section, for illustrating how the disc-shaped conveying members are fastened to the conveying wire in another embodiment;

Fig. 3 shows a perspective view of an embodiment of a single disc-shaped conveying member according to the invention;

Fig. 4 shows a plan view, partly in section, of a further embodiment of a conveying wire according to the invention, where the outermost end parts of the discshaped conveying members are made of the same softer material as the outer jacket;

Fig. 5 shows three views A-C for illustrating a method for making a conveying wire according to the invention in three method steps;

Fig. 6 shows two views A-B of a conveying wire according to the invention made by the method of Fig. 5;

Fig. 7 shows three views A-C for illustrating a method for making an alternative conveying wire according to the invention in three method steps;

Fig. 8 shows two views A-B of a conveying wire according to the invention made by the method of Fig. 7; and

Fig. 9 shows a draft of an embodiment for a plant for use in making a conveying wire according to the invention.

Detailed Description of Embodiments of the Invention

The conveying wire 2 shown in Figs. 1 -3 includes a twisted or plaited fibre wire 3 (basic wire) consisting either of a number of twisted strands or of a number of plaited strands that each are made of thin threads or fibres made up of synthetic plastic. The conveying wire 2 also includes a number of disc-shaped conveying members 4 which are fastened by injection moulding directly to the fibre wire 3 and to an outer jacket 6 which is similarly fastened by injection moulding directly to the fibre wire 3.

The outer jacket 6 extends over sections 8 of the wire at least between the conveying members 4 as opposing end parts 10 of the sections 8 continue in under opposing end parts 14 of the conveying members 4.

As shown at the left side of Fig. 2, an end part 10 of the outer jacket 6 or section 8 designed with an annular bead or thickening 12 which during the subsequent injection moulding of conveying member 4 initially has the task of ensuring an optimal connection between the end parts 10 and 14.

By injection moulding the outer jacket 6 (coating) directly around the fibre wire 3, there is achieved - as opposed to traditional extrusion - a significantly better permanent adherence between the outer jacket 6 and the fibre wire 3, due to the high moulding pressure (400-500 bar).

Immediately before injection moulding of the conveying members 4 around the fibre wire 3, the outer jacket 6 is also moulded around the fibre wire 3. There is a large degree of freedom when deciding how the outer jacket 6, or more correctly, its sections 8 are to be designed. As described above, the sections 8 can be designed at opposing end parts 10 with a bead or thickening 12.

Alternatively, the end parts 10 can be without the said bead or thickening as the end parts 10 of course are intended to continue in under the end parts 14 of the conveying members 4.

According to a further embodiment, sections 8 on the fibre wire 3 can have a very narrow spacing as by the subsequent injection moulding of the conveying members 4 there will automatically be performed an adjusting of opposing end parts 10 of the sections 8 in that excessive parts are simply melted away or integrated with the end parts 14 of the conveying members 4.

Or the outer jacket 8 may, if possible, be injection moulded around the fibre wire 3 entirely without spacing because by the subsequent injection moulding of the conveying members 4 there may automatically occur a melting away of parts of the outer jacket 8 such that the conveying members 4 are fastened directly to the fibre wire 3. The most important common feature by the described embodiments is that the outer jacket (coating) 8 is fastened directly to the fibre wire 3 by high pressure injection moulding.

Fig. 4 shows an alternative embodiment where outermost end parts 16 of the conveying members 4 consist of the same soft material as the outer jacket 6. By the subsequent injection moulding of the conveying members 4, it may be supposed to a lesser extent that the outermost end parts 16 are softened and melted together/integrated with the conveying members 4.

The softer outermost end parts 16 entail an obvious, though very important advantage, namely that the bending radius of the conveying wire 2 in this embodiment generally becomes less. Or, in other words, the conveying wire 2 as a unit becomes more flexible and therefore more easily can run about reversing or corner wheels with reduced diameters.

Fig. 5 shows three views A-C for illustrating a method for making a conveying wire 2 according to the invention, wherein separated outer jacket parts 18 with a specific shape, cf. Fig. 5B, are fastened by injection moulding directly on a fibre wire 3 (Fig. 5A) at first. After that, disc-shaped conveying members 20, cf. Fig. 5C, are fastened by injection moulding directly on the fibre wire 3 in interspaces 22 between the outer jacket parts 18. The last part of the injection moulding of the disc-shaped conveying members 20 occurs in such a way that opposing end parts 24 of the outer jacket members 18 extend in under foot parts 26 of the disc-shaped conveying members 20. Fig. 6 A shows a view of a longitudinal section on the line VI- VI in Fig. 6B, showing an end view, partly in section, of a conveying wire 2 with disc-shaped conveying members 20 wherein it can be seen that the end parts 24 extend in under the foot parts 26 of the disc-shaped conveying members 20. Fig. 7 shows three views A-C for illustrating a method for making a conveying wire 2 according to the invention, wherein mutually separated outer jacket parts 28 with a specific shape, cf. Fig. 7B, are fastened by injection moulding directly on a fibre wire 3 (Fig. 7A). Then disc-shaped conveying members 30, cf. Fig. 7C, are fastened by injection moulding directly on the fibre wire 3 in interspaces 22 between the discshaped conveying members 28 which at opposite sides comprise relatively long, outwardly tapering foot parts 34. The last part of the injection moulding of the outer jacket parts 30 occurs in such a way that opposing end parts 36 of the outer jacket members 30 extend in over the relatively long foot parts 34 of the disc-shaped conveying members 28.

Fig. 8A shows a view of a longitudinal section on the line VIII- VIII in Fig. 8B, showing an end view, partly in section, of a conveying wire 2 with disc-shaped conveying members 28 wherein it can be seen that the opposing end parts 36 of the outer jacket parts 30 extend in under the relatively long foot parts 34 of the discshaped conveying members 28.

Fig. 7B shows that the relatively long foot parts 34 of the disc-shaped conveying members 28 are designed with an annular concave recess 38 in which a ring-shaped bead 40, more clearly seen in Fig. 8A, of opposing end parts of outer jacket parts 30 engage. It will be understood that a conveying wire 2, cf. Fig. 7C and Fig. 8A, respectively, has a flexibility that makes the conveying wire 2 well suited for running through relatively narrow turns (corner wheels with relatively small diameter).

Fig. 9 shows a drawing of an embodiment of a production plant for making a conveying wire 2 according to the invention, where a fibre wire 3 is unwound from a supply roll 42, which for the purpose of keeping the fibre wire 3 in tension is e.g. weight loaded clockwise (illustrated by curved arrow 44 and weight 46). The direction of production is illustrated by arrows 48.

The fibre wire 3 runs over a guide wheel 50 into an injection moulding machine 52 where disc-shaped conveying members and outer jacked parts, respectively, are fastened directly to the fibre wire 2 such that the conveying wire 2 to the left of the injection moulding machine 52 runs through a cooling zone 54, over a further guide wheel 56 to winding station 58, which for the purpose of keeping the conveying wire 2/fibre wire 3 in tension is weight loaded counterclockwise (illustrated by curved arrow 60 and weight 62); alternatively a spring or other resisting means can be applied.

It will be understood that the sequence of fastening disc-shaped conveying members and outer jacket parts directly on the fibre wire 3 by injection moulding, cf. the above, can be varied according to wish.

Finally, it is to be noted that the fibre wire 3 may consist of aramide (aromatic polyamide), Technora (aromatic polyamide/copolymer), aromatic liquid polyester fibre (Vectran fibre) or ultra high molecule weight polyethylene (Dynema- and Spectra fibre).

A common feature of these fibres is a relatively high elastic modulus (75GPa - 135 GPa), and in addition, the fibres themselves can be parallel, twisted or plaited to form cordage. Due to the high elastic modulus, it is counteracted that the fibres are extended like elastic piping under load.

Reference numbers of the drawing:

2 conveying wire

3 twisted or plaited fibre wire

4 disc-shaped conveying members

6 outer jacket (coating)

8 outer jacket parts

10 opposite end parts of outer jacket parts

12 beads or thickenings

14 opposing foot parts of disc-shaped conveying members

16 outermost foot parts of soft material

18 outer jacket parts

20 disc-shaped conveying members

22 interspaces between outer jacket parts

24 opposite end parts of outer jacket parts

26 foot parts of disc-shaped conveying members

28 disc-shaped conveying members

30 outer jacket parts

32 interspaces between disc-shaped conveying members

34 relatively long, outward tapering foot parts

36 opposite end parts of outer jacket parts

38 annular concave recess

40 annular bead

42 supply roll

44 curved arrow (clockwise)

46 weight

48 arrows showing production direction

50 guide wheel

52 injection moulding machine

54 cooling zone

56 guide wheel

58 winding station

60 curved arrow (counterclockwise)

62 weight