EP3054049A1

EP3054049A1 - Cable stranding machine

Info

Publication number: EP3054049A1
Application number: EP16154257.6A
Authority: EP
Inventors: Massimo Parise; Paolo Pattacini
Original assignee: Euroalpha Srl
Current assignee: Sampsistemi Srl
Priority date: 2015-02-04
Filing date: 2016-02-04
Publication date: 2016-08-10
Anticipated expiration: 2036-02-04
Also published as: EP3054049B1; ES2671611T3

Abstract

A cable stranding machine (10), characterized in that it comprises:
- a stranding rotor (11), provided with a pulley supporting arm (12),
- means (13) for support and translation in an axial direction of the stranding rotor (11), for the layering of the cable carried out on a spool and
- spool holder supporting means (14), of the type with tailstocks, axially locked in the operating configuration.

Description

The present invention relates to a cable stranding machine.
The invention relates to the sector of cable stranding machines.
In particular, the invention relates to the area of twist cable stranding machines for manufacturing strands or cords.
Traditionally known in the sector as "single twist", such type of machine can also be used for carrying out a mechanical reinforcement of a cable that has already been stranded, for example cables for providing electricity lines.
Nowadays, a peculiar problem of conventional cable stranding machines consists in mounting spools of great weight, which must be rotated at high rotation speeds.
The DIN 46395 standard, which standardizes the dimensions of the spools used on cable stranding machines, requires an axial hole for coupling to a support for the spool which in relative terms is very small with respect to the weight that can be reached by the spool during collection of the cable.
The great weight induces high mechanical stresses on all parts that are intended to support the spool, limiting the maximum speed of production that can be reached.
The cable stranding machines on the market today can be grouped into three types, each of which solves the above mentioned drawback differently.
A first type of cable stranding machines, for small-sized spools, up to a flange diameter of 1000 mm, comprises:

a motorized rotor, or flyer, substantially C-shaped, which by rotating about its own axis twists together the filaments that make up a cable, and diverts them by way of pulleys toward a spool on which the cable is wound;
a carriage with a cantilevered shaft, coaxial to the rotor, on which the spool is mounted; such carriage is motorized in order to translate in a direction parallel to the rotation axis of the rotor and the spool in order to perform the ordered layering of the coils of cable on the spool; the spool is supported, in a cantilever arrangement, between the arms of the motorized rotor; also mounted on the carriage is the actuation of the spool; such spool rotates in the same direction as the rotor at a slightly greater/lower speed in order to wind the cable that has just been made around itself.

Such a machine is disclosed, for example, in European patent application EP0801166A2 .
Such first type of cable stranding machines exhibit a significant limitation which is constituted by the cantilevered shaft for supporting the spool; the rotation speed of the rotor, or flyer, is in fact limited by the rotation speed beyond which the bending of the rotating shaft is considered critical.
A second type of cable stranding machines, for large-sized spools, with a flange diameter starting from 1250 mm, supports the spool between two tailstocks, as disclosed and illustrated, for example, in US2817948 and US4389838 .
In such second type of cable stranding machines the rotor, or flyer, is substituted by a substantially annular rotor, supported between two shoulders, in the internal space of which is accommodated, coaxial, the spool for winding the cable.
The layering of the cable on the spool can be carried out either by translation of the spool in the internal space of the rotor, or with means of translation of the last pulley, for redirecting the cable toward the spool, on the rotor proper.
The rotor is usually of the supporting type, i.e. it is structured so as to support the spool, between two tailstock centers, and part of the means for moving it.
The rotating shaft of the spool is therefore not cantilevered, as in the first type of cable stranding machines described previously.
The limitation of such second type of cable stranding machine therefore lies in the fact that it has an annular rotor of large size and the mass and inertia of this imposes limits on the rotation speed and as a consequence on the rate of production.
A third type of cable stranding machines, an example of which is in EPA 2398957A1 , has a C-shaped or L-shaped rotor, or flyer, which is made rotate by a corresponding hollow driving shaft and respective support and drive means, and a spool supported by tailstocks, i.e. without a shaft passing through it; a first tailstock is supported by a first support on which are also mounted the means of driving the spool, while the second, opposite tailstock is supported by a rotating shaft passing through the hollow driving shaft of the rotor and coaxial with it, such rotating shaft being placed on an external support and on the rotor proper.
The layering of the cable on the spool occurs by way of translation of the spool in an axial direction.
In order to move the spool, both the support of the first tailstock and the external support of the rotating shaft which supports the second tailstock are motorized and arranged so that they slide on corresponding guides.
Such third type of cable stranding machines combine a relatively light rotor with the rigidity and, at the same time, the agility of the tailstocks for supporting the spool.
The limitation of such third type of cable stranding machines is the complicated construction, which entails high production costs and maintenance costs; for example, the rotating shaft that supports the second tailstock is very long and at high speed it tends to bend with consequent heavy stresses on the bearings on which it rests.
Furthermore, in addition to the axial hole for the filaments for making the cable, the rotating shaft is provided with a longitudinal groove in which a first pulley must be free to rotate to redirect the cable toward the outer part of the rotor, from which the cable is then deviated toward the spool, such first pulley being mounted on the rotor proper; such longitudinal groove, in addition to requiring precision machining, mechanically weakens the rotating shaft proper.
Furthermore, the simultaneous and synchronized movement of the support of the first tailstock and of the external support of the rotating shaft that supports the second tailstock requires the fine-tuning of a complex and articulated mechanical transmission, based for example on the use in series of a plurality of universal joints or right-angle transmissions, components which in addition to attracting a cost are very delicate and costly in terms of maintenance.
The aim of the present invention is to provide a cable stranding machine which is capable of overcoming the above mentioned drawbacks of conventional machines.
Within this aim, an object of the invention is to provide a cable stranding machine that is capable of operating at higher speeds than both annular rotor machines and machines with the spool supported in a cantilever arrangement.
Another object of the invention is to provide a cable stranding machine that is at least as strong and efficient as conventional machines.
Another object of the invention is to provide a cable stranding machine that is simple to assemble and less burdensome to maintain than conventional machines.
This aim and these and other objects which will become better evident hereinafter are achieved by a cable stranding machine, which is characterized in that it comprises:

a stranding rotor, provided with a pulley supporting arm,
means for support and translation in an axial direction of said stranding rotor, for the layering of the cable carried out on a spool and
spool holder supporting means, of the type with tailstocks, axially locked in the operating configuration.

Further characteristics and advantages of the invention will become better apparent from the detailed description that follows of a preferred, but not exclusive, embodiment of the cable stranding machine according to the invention, which is illustrated for the purposes of non-limiting example in the accompanying drawings wherein:

Figure 1 is a schematic, partially cross-sectional side view of a cable stranding machine according to the invention;
Figure 2 is the same view as Figure 1 in a first operating configuration of the cable stranding machine according to the invention;
Figure 3 is the same view as Figures 1 and 2 in a second operating configuration of the cable stranding machine according to the invention;
Figure 4 is a schematic side view of a variation of embodiment of the cable stranding machine according to the invention;
Figure 5 is a schematic side view of a further variation of embodiment of the cable stranding machine according to the invention.

With reference to the figures, a cable stranding machine according to the invention is generally designated, in a first embodiment thereof, with the reference numeral 10.
The cable stranding machine 10 comprises:

a stranding rotor 11, provided with a pulley supporting arm 12, in a cantilever arrangement in the present embodiment,
means 13 for support and translation in an axial direction of the stranding rotor 11, for the layering of the cable carried out on a spool, and
spool holder supporting means 14, of the type with tailstocks, fixed axially in the operating configuration.

The main axis, of rotation for the rotor 11 and for the spool holder supporting means 14, shown in Figure 1 as supporting a generic spool 15, is designated with the reference letter X.
The stranding rotor 11 comprises a tubular body 16, which is arranged so that it rotates inside a tubular jacket 17 by interposition of friction reduction means, for example bearings 18 and 19.
The means 13 for support and translation in an axial direction of the stranding rotor 11 comprise a motorized base 20, arranged so that it can slide on a corresponding guide 21; the motorized base 20 supports the tubular jacket 17, the latter being fixed to the motorized base.
The motorized base 20 is moved translationally by corresponding actuator means 22.
The actuator means 22 are constituted, for example, by an electric motor 23 with belt or chain transmission 24, adapted to rotate a threaded bar 25 which is coupled with one or more complementarily threaded translation screws 26 which are fixed to the motorized base 20.
The motor means for the rotation of the stranding rotor 11 are mounted on the motorized base 20.
Such motor means are constituted, for example, by an electric motor 27 with transmission of the power to the rotor 11 by way of a belt or chain 28.
The spool holder supporting means 14, of the type with tailstocks, comprise a first tailstock center 29, supported by a column-like element 30 on the opposite side with respect to the stranding rotor 11.
The first tailstock center 29 is supported by a first tailstock center supporting shaft 31, which also supports a flywheel 32 which is adapted to turn the spool 15; the flywheel 32 is made rotate by a corresponding motor 33, for example by way of a transmission belt 34.
The first tailstock center supporting shaft 31 can be translated axially by way of a corresponding actuator 35 for inserting and extracting the first tailstock center 29 into/out of the axial hole of the spool 15.
The actuator 35 is constituted for example by a linear actuator of the screw and translation screw type.
The spool holder supporting means 14 comprise a second tailstock center 36, supported by a second tailstock center supporting shaft 37 the end portion 38 of which, opposite to the second tailstock center 36, is arranged so that it rotates, on corresponding friction reduction means, within a supporting body 39, which is locked in a stable position when the rotor 11 is operative.
The supporting body 39 and the second tailstock center supporting shaft 37 are axially perforated for the passage of filaments 40 that are adapted to be stranded by the stranding rotor 11.
The second tailstock center supporting shaft 37 also supports a first pulley 41 for redirecting filaments of stranding cords 40 toward the cantilever pulley supporting arm 12.
The second tailstock center supporting shaft 37, which supports the first pulley 41, rotates together with the stranding rotor 11, supporting, on the cantilever arm 12, other transmission pulleys 43 and 44, by way of adapted means for transmitting the rotary motion from the stranding rotor 11 to the second tailstock center supporting shaft 37.
The means for transmitting rotary motion comprise an intermediate body 42 for connection between the stranding rotor 11 and the second tailstock center supporting shaft 37; the intermediate body 42 is rigidly connected to the second tailstock center supporting shaft 37 and is connected to the stranding rotor 11 by way of a prismatic coupling.
Such prismatic coupling is constituted, for example, by a longitudinal guiding groove 46 defined on the outer surface of the intermediate body 42 and by a slider 47 which is arranged to slide in it and is fixed to the stranding rotor 11.
Thanks to such coupling the rotating motion of the rotor 11 and the rotating motion of the second shaft 37 are synchronous.
The supporting body 39 is constituted by a tubular part 49, coaxial to the rotor 11 and to the two tailstock centers 29 and 36 and internally hollow for the passage of filaments 40 for stranding, and by a column-like part 50 which supports the tubular part 49 in a cantilever arrangement.
The column-like part 50 rests on means 51 for its translation in an axial direction X.
The means of translation 51, which are constituted for example by a screw and translation screw 52 drive unit and by a sliding base on guides 53, are adapted to make the supporting body 39 translate, and with it the second tailstock center supporting shaft 37 with the second tailstock center 36, for inserting and extracting the second tailstock center 36 into/out of the axial hole of the spool 15.
The intermediate body 42 is beaker-shaped and is arranged so as to surround the end portion 54 of the tubular part 49 of the supporting body 39 inside which the end portion 38 of the second tailstock center supporting shaft 37 is inserted.
The intermediate body 42 is simultaneously inserted inside the tubular body 16 of the stranding rotor 11.
The slider 47 protrudes from the inner surface of the tubular body 16.
The intermediate body 42 is therefore supported by the second tailstock center supporting shaft 37, which is in turn supported by the supporting body 39.
Operation of the cable stranding machine according to the invention is the following.
Once the spool 15 is positioned between the first and second tailstock centers 29 and 36, the stranding of the filaments and the winding of the cable onto the spool 15 occur with the spool not moving in the direction of its rotation axis X, while the stranding rotor 11 rotates about the same axis X and performs a translational motion with alternating motion in the direction of the same axis X by way of the action of the means 13 for support and translation.
Figure 2 schematically shows a first stroke limit position of the alternating translational motion of the rotor 11, while Figure 3 schematically shows the second, opposite stroke limiting position.
By actuating the translation actuator 35 for the first tailstock center supporting shaft 31 and the means of translation 51 for the supporting body 39, and therefore for the second tailstock center supporting shaft 37, the disengagement is obtained of the first and second tailstock centers 29 and 36 from the axial hole of the spool 15, for the removal of the spool 15.
The locking of a new spool between the tailstocks is achieved with an opposite operation.
In a variation of embodiment of the cable stranding machine according to the invention, shown schematically in Figure 4 and generally designated therein with the reference numeral 110, the means for transmitting rotary motion from the stranding rotor 111 to the second tailstock center supporting shaft 137 are constituted by a mechanism for deviating the rotary motion of the stranding rotor 111 directly to the second tailstock center supporting shaft 137, rather than by way of an intermediate body 42 with guide 46 and slider 47 as described above for the first embodiment.
As already described above, such second tailstock center supporting shaft 137 is arranged so that it rotates, on corresponding friction reduction means, inside the supporting body 139, which is locked in a stable position when the rotor 111 is operative.
The second tailstock center supporting shaft 137 is axially perforated for the passage of filaments 140 that are adapted to be stranded by the stranding rotor 111.
The second tailstock center supporting shaft 137 supports the first pulley 141 for redirecting the stranding cords 140 toward the cantilever pulley supporting arm 112.
In such variation of embodiment the second tailstock center supporting shaft 137 is provided with a portion 138, opposite the tailstock center 136, which is extended along the entire length of the tubular part 149 of the supporting body 139, until it protrudes therefrom.
The end of the portion 138 protruding from the tubular part 149 is provided with a pulley 160.
The motor 127, which is integral with the base 120, for example by way of the tubular jacket 117, supports the rotor 111 in rotation by way of a belt 128, as already described above.
The mechanism for deviating the rotary motion from the rotor 111 to the second tailstock center supporting shaft 137 is constituted, for example, by a second belt 161 which is adapted to transmit the rotation from a pulley 162 which is integral with the rotor 111 to an intermediate transmission shaft 163, with end transmission pulleys 165 and 166, which is in turn connected by way of a third belt 164 to the pulley 160, which is fixed at the end of the portion 138 of the second tailstock center supporting shaft 137.
The end transmission pulley 165, i.e. the pulley whose second belt 161 is moved directly by the rotor 111, in addition to rotating, slides on the intermediate transmission shaft 163 by way of a sliding coupling, which is determined for example by the broaching of a portion of that shaft.
The pulleys 160 and 162 and the end pulleys 165 and 166 of the intermediate transmission shaft 163 are dimensioned so that the transmission ratio is 1:1 and the rotation of the rotor 111 and of the second tailstock center supporting shaft 137 is synchronous.
In a further variation of embodiment of the cable stranding machine according to the invention, shown schematically in Figure 5 and generally designated therein with the reference numeral 210, the stranding rotor 211, in addition to the pulley supporting arm 212, is also provided with at least another auxiliary arm 270, and such cantilever arms 212 and 270 support an annular flywheel 271 for containing the centrifugal forces on the pulley supporting arm 212 and on the pulleys proper.
The one or more auxiliary arms 270 are arranged symmetrically together with the pulley supporting arm 212.
In practice it has been found that the invention fully achieves the intended aim and objects.
In particular, with the present invention a cable stranding machine has been devised which is capable of operating at higher speeds than both annular rotor machines and machines with the spool supported in a cantilever arrangement, thanks to the spool holder supporting means 14 of the type with tailstocks and to the light stranding rotor 11, in that it is not annular and it has a single arm in a cantilever arrangement with only two pulleys 43 and 44, differently from what is described for conventional cable stranding machines of the first and second type described above.
Moreover, with the invention a cable stranding machine has been devised which is at least as strong and efficient as conventional machines, thanks to its simplicity of construction, with no long shafts subjected to translation and to rotation, and with no articulated means for transmitting the motion between two opposing parts of the same machine, as in the third type of conventional cable stranding machines.
Also, with the invention a cable stranding machine has been devised which is simple to assemble and simpler to maintain than conventional machines.
Moreover, with the invention a cable stranding machine has been devised which combines the rigidity of the tailstocks solution with the lightness of the stranding rotor as described above, a solution that is achieved by mounting the first, input pulley not on the rotor proper but on the second tailstock center supporting shaft, thus allowing the stranding rotor to translate in order to perform the layering of the cable on the spool, while in the known art the input pulley is mounted on the rotor and so prevents the translational movement of the entire rotor.
Another advantage of the invention consists in that the cable stranding machine according to the invention enables the assembly of spools with hole conforming to the DIN 46395 standard.
Moreover, with the invention a cable stranding machine has been devised which is capable of high production speeds even with heavy spools.
Furthermore, with the invention a cable stranding machine has been devised which has no size restrictions, thanks to the reduced mass of the mechanical elements made to rotate.
Furthermore, with the invention a cable stranding machine has been devised which has no sliding-contact commutator for the electrical connection of devices mounted on the rotating part, to the advantage of the low cost of construction and of the simplicity of both construction and maintenance.
The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Moreover, all the details may be substituted by other, technically equivalent elements.
In practice the components and the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements and to the state of the art.
The disclosures in Italian Patent Application No. PD2015A000025 ( 102015902327760 ) from which this application claims priority are incorporated herein by reference.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

A cable stranding machine (10), which is characterized in that it comprises:
- a stranding rotor (11), provided with a pulley supporting arm (12),

- means (13) for support and translation in an axial direction of said stranding rotor (11), for the layering of the cable carried out on a spool and

- spool holder supporting means (14), of the type with tailstocks, fixed axially in the operating configuration.
The cable stranding machine according to claim 1, characterized in that said stranding rotor (11) comprises a tubular body (16), arranged so that it rotates inside a tubular jacket (17) by interposition of friction reduction means.
The cable stranding machine according to one or more of the preceding claims, characterized in that said means (13) for support and translation in an axial direction of the stranding rotor (11) comprise a motorized base (20), arranged so that it can slide on a corresponding guide (21), said motorized base (20) supporting said tubular jacket (17), the latter being fixed to the motorized base.
The cable stranding machine according to one or more of the preceding claims, characterized in that said motorized base (20) is moved translationally by corresponding actuator means (22).
The cable stranding machine according to one or more of the preceding claims, characterized in that the motor means for the rotation of the stranding rotor (11) are mounted on said motorized base (20).
The cable stranding machine according to one or more of the preceding claims, characterized in that said spool holder supporting means (14), of the type with tailstocks, comprise a first tailstock center (29), supported by a column-like element (30) on the opposite side with respect to the stranding rotor (11), said first tailstock center (29) being supported by a first tailstock center supporting shaft (31), and a second tailstock center (36), supported by a second tailstock center supporting shaft (37), the end portion (38) of which, opposite the second tailstock center (36), is arranged so that it rotates, on corresponding friction reduction means, within a supporting body (39), which is locked in a stable position when the rotor (11) is in operation.
The cable stranding machine according to one or more of the preceding claims, characterized in that said first tailstock center supporting shaft (31) can be translated axially by way of a corresponding actuator (35) for inserting and extracting the first tailstock center (29) into/out of the axial hole of the spool (15).
The cable stranding machine according to one or more of the preceding claims, characterized in that said second tailstock center supporting shaft (37) also supports a first pulley (41) for redirecting the stranding cords (40) toward the cantilever pulley supporting arm (12).
The cable stranding machine according to one or more of the preceding claims, characterized in that said second tailstock center supporting shaft (37), which supports the first pulley (41), rotates together with the stranding rotor (11) by way of adapted means for transmitting the rotary motion from the stranding rotor (11) to the second tailstock center supporting shaft (37).
The cable stranding machine according to one or more of the preceding claims, characterized in that said means for transmitting rotary motion comprise an intermediate body (42) for connection between the stranding rotor (11) and the second tailstock center supporting shaft (37); said intermediate body (42) is rigidly connected to the second tailstock center supporting shaft (37) and is connected to the stranding rotor (11) by way of a prismatic coupling.