EP2818594B1 - Wire rope and method of manufacturing the same - Google Patents

Description

The invention relates to a method for production and to a wire rope according to the preamble of claim 1 or 6, and a device according to the preamble of claim 12.

With a wire rope according to the publication EP-A-1 040 221 a cylindrical core with several wire strands stranded around it are provided. In addition, between each adjacent pair of strands, filling elements are arranged, which are made of a polymeric or elastomeric material and have an oriented molecular structure. Each of these filling elements is assigned a widened foot section which fills the space formed between two strands and the core and can thus rest on the central core.

With this cylindrically designed core, when the wire rope is in operation, after a certain initial operating time, a flow in the radial direction outwards forms, as a result of which grooves adapted to the outer contours of the wire strands are created on the circumference of the core. However, this is associated with various disadvantages, in particular creeping and thus an extension of the entire wire rope occurs Operation, which must be compensated again. In addition, the rope diameter also changes during operation, which must be taken into account when installing the same.

In the pamphlet DE-A-1 071 543 it is mentioned that these spiral ridges are attached as immovable stops on the core. These can be thermally deformable or sprayed on by resistance welding or when using plastic.

With the print DE-A-711 238 Again, claim 1 defines that the core is compressed and preformed by pressing prior to stranding. This is achieved by using a press pass in the same operation as the rope is manufactured.

With the wire rope according to the publication GB-A-2 269 400 the cylindrical body and one outer body are grooved with helical grooves. All that is mentioned is that the outer body is brought into an extruder and thus a second extrusion step takes place in addition to the central body.

With a thread cutting head according to the publication DE-A-451 015 the tool head is designed to be non-rotatable and these approximately radially adjustable cutting tools are suitable for producing threads, but not for grooves for inserting strands in a wire rope.

The present invention is based on the object of creating a method for the production of a wire rope by means of which the properties of the wire rope are improved, in particular with regard to the smoothness and internal cohesion.

According to the invention, this object is achieved by a method according to the features of claim 1 or by a wire rope according to the features of claim 6 or a device according to the features of claim 12.

This design of the wire rope with this machining to produce helical grooves in the plastic core an optimal guidance of the wire strands in the stranded state is achieved and this results in various improvements in the properties of the wire rope as a whole.

With the inventive method of performing this machining for the production of the helical grooves immediately before the wire strands are stranded around the plastic core, the advantage arises that these helical grooves are provided with absolutely the same lay length as the wire strands.

Fig. 1

eine schematische Darstellung der Herstellung eines erfindungsgemässen Drahtseils, von welchem die Kunststoffseele und drei der Drahtlitzen je in Teillänge veranschaulicht sind; und

Fig. 2

ein erfindungsgemässes Drahtseil im Querschnitt.

Exemplary embodiments and further advantages of the invention are explained in more detail below with reference to a drawing. It shows:

Fig. 1

a schematic representation of the production of a wire rope according to the invention, of which the plastic core and three of the wire strands are each illustrated in partial length; and

Fig. 2

a wire rope according to the invention in cross section.

Fig. 1 shows the production of a wire rope 10 with a plastic core 11 and several wire strands 15 stranded around it, only three of the total of six wire strands being shown for better clarity.

Such wire ropes are suitable, for example, for use in rail vehicles that are pulled by the wire ropes that are guided on rollers or the like between the rails.

According to the invention, a helical groove 20 is produced by machining on the circumference of the plastic core 11 for each wire strand 15, these helical grooves 20 being adapted to the outer diameter of the wire strands 15.

The wire strands 15 are stranded around this plastic core 11, which is moved in the axial direction at a feed rate, and they are wound around the plastic core 11 at a certain speed and feed speed. The plastic core 11 is provided with these helical grooves 20 by machining immediately before the wire strands 15 are wound onto them.

This inventive machining of the plastic core 11 supplied as a cylindrical rod 11 'from a flexible plastic is carried out by means of a machining device 25 in which cutting tools 26 are rotated at the same speed as the wire strands 15 around the plastic core 11 for the production of the helical grooves. The cutting tools 26 are directed with their cutting against the direction of movement of the plastic core. A tool clamping holder 27 is assigned to each cutting tool 26 and is fastened in a radially adjustable manner to a tool head 25 which is rotatable with a central opening for the passage of the rod 11 '. The respective tool clamping holder 27 consists of a chuck 28 and an adjustment module, not shown in detail, by means of which the cutting tool 26 can be precisely adjusted to the diameter of the plastic core 11. The rotary drive of the tool head 25 as well as the coils with the wire strands 15 wound thereon are not illustrated in more detail.

The wire strands 15 and the plastic core 11 are drawn through an annular mandrel 22 in the axial direction at the same feed rate. The wire strands 15 are advantageously preformed with a helical shape when being fed in for stranding and are drawn together with the plastic core, whereby they are pressed the wire strands against the plastic core by this mandrel 22, while these grooves 20 serve as a guide for the wire strands 15.

Fig. 2 shows a wire rope 10 with a plurality of wire strands 15 made from stranded wires 16, which are stranded around a plastic core 11 and elongated inserts 12 are arranged between them. These inserts 12, which extend over the entire length of the rope, are shaped in their cross section in such a way that they extend approximately to the outer circumference of the wire rope 10. In this case, they are provided on the outer circumference with a radius R which corresponds approximately to half the rope diameter, in order, together with the wire strands 15, to form an approximately uniform outer diameter. In the area in contact with the wire strands 15, they each have a radius corresponding to the wire strands 15 on both sides.

Such wire ropes 10 are used in particular as traction or conveyor ropes with high load requirements, for example in cable cars which are suspended from a stationary support rope and connected to a traction rope. Pulling or conveying ropes are usually guided around pulleys at the upper and lower stations and designed as endless ropes by splicing their ends or held together by an end attachment, which is not shown in detail.

The stranded wire strands 15 rest over a certain circumferential area in the grooves 20 directly on the plastic core 11, while the inserts 12 are each arranged on the inside at a distance a from the plastic core 11.

When using a total of six wire strands, this groove 20 in a respective wire strand 15, in which it rests directly on the plastic core 11, corresponds to an angular range of a respective wire strand based on its cross section of preferably between 40 ° and 60 °. These helical grooves 20 are designed to be round in the transverse step with a radius which corresponds approximately to half the diameter of a wire strand 15.

The distances a between the inserts 12 and the plastic core 11 are each dimensioned in such a way that they correspond at least approximately to an extent that is created by the radial outward flow of the plastic core 11 after a certain initial operating time of the wire rope. This expansion is in the millimeter range depending on the diameter of the core and the load on the wire rope.

The inserts 12 each have a thickness d 'with their inside end part 12' protruding between two wire strands 15 which is greater than the thickness d in the narrowest area of the respective insert 12, these inside end parts 12 'outside an imaginary one Circle 14 end at the inner sides of the wire strands 15, as shown in phantom. This inner end part 12 'of the inserts 12 is rounded off, but could also be elliptical, half-polygonal or even flat.

The invention is sufficiently demonstrated with the exemplary embodiments explained. Of course, they could also be illustrated by other variants, in which, for example, instead of six, a different number of wire strands could be used.

Claims (13)

1. A method of producing a wire rope, which is produced by at least one plastic core (11) and number of wire strands (15) stranded around it, whereby a helical groove (20) is respectively produced around the periphery of the plastic core (11) for each wire strand (15), characterised in that
   these helical grooves (20) are produced by machining, whereby they are being matched in the cross section respectively to the outside diameter of the wire strands (15).
2. The method according to Claim 1, characterised in that the wire strands (15) are being stranded around a plastic core (11), which is moved with a feed in the axial direction, whereby the wire strands (15) are being wound around the plastic core (11) with a specific rotation speed and feed speed, whereby the plastic core (11) is provided with the helical grooves (20) for receiving the wire strands (15) by machining directly before the wire strands (15) are wound onto said core.
3. The method according to Claim 2, characterised in that for the production of the helical grooves the cutting tools (26) used for the machining of the plastic core (11) are rotated around the plastic core (11) with the same rotation speed as the wire strands (15).
4. The method according to Claim 2 or 3, characterised in that these wire strands (15) and the plastic core (11) are drawn in the axial direction with the same feed speed.
5. The method according to any one of the preceding Claims 2 to 4, characterised in that when being introduced for twisting, the wire strands (15) are pre-formed in a helical shape and are drawn together with the plastic core (11) by an annular mandrel (22) by means of which these wire strands are pressed against the plastic core.
6. A wire rope, produced by the method according to any one of the preceding Claims 1 to 5, comprising at least one plastic core (11) and a number of wire strands (15) twisted around it, whereby a helical groove (20) is respectively produced around the periphery of the plastic core (11) for each wire strand (15), characterised in that the helical grooves (20) are cut by of the plastic core (11) and are formed with a round cross-section with a radius which corresponds approximately to half the diameter of a wire strand (15).
7. The wire rope according to Claim 6, characterised in that the plastic core (11) is produced in the form of a bar from a flexible plastic.
8. The wire rope according to any one of the preceding Claims 6 or 7, characterised in that when using six strands, the wire strands (15) guided within the helical grooves (20) lie in an angular range of a respective wire strand of up to 60° in relation to the cross section.
9. The wire rope according to any of the preceding Claims 6 to 8, characterised in that there is respectively disposed between the wire strands (15) consisting of stranded wires (16) an elongate insert (12), which inserts extend almost to the outer circumference of the wire rope (10), however, on the inside being arranged a distance (a) away from the plastic core (11).
10. The wire rope according to Claim 9, characterised in that the inserts (12) respectively with their inside end part (12') projecting through two strands (15) respectively have a thickness (d'), which is greater than the thickness (d) in the narrowest region of the respective insert (12), whereby these inside end parts (12') ending outside of a notional circle (14) on the insides of the strands (15).
11. The wire rope according to Claim 9 or 10, characterised in that the inserts (12) are provided on the outer circumference with a radius (R) corresponding to almost half the rope diameter in order to form an almost equal outside circumference with the strands (15).
12. A device with a machining device for the production of a wire rope for implementing the method according to any of the Claims 1 to 5, with an annular mandrel (22) by means of which these wire strands (15) and the plastic core (11) are drawnable and these wire strands are pressable against the plastic core, characterised in that the machining device (25) is provided with a rotatable tool head (25) with a central opening and with radially adjustable cutting tools (26), whereby the central opening of the tool head (25) is provided for passing through the plastic core (11) for producing the helical grooves (20) by these cutting tools (26).
13. The device according to Claim 12, characterised in that with the machining device there is assigned to each cutting tool (26) a clamping tool holder (27), which is respectively fastened radially adjustable to the tool head (25).

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