FR2477584A1 - Cable of strands of metal wires - having spiral twist of the same direction and pitch - Google Patents

Abstract

A cable of metal wires is made up of at least two strands, having a spiral twist of the same direction and pitch. The strands are twisted around an axis outside their own axes, and are assembled by overlapping the spirals formed, one within the other. The strands are multifilament bindles, containing identical wires, or wires having different diameters. At least one of the filament bundles is twisted on itself so that the pitch of the spiral is greater than fifty times the diameter of the largest wire in the bundle. Preferably, the cable has several multi-filament bundles twisted on themselves.

Description

 The present invention relates to articles such as strands or wire ropes for reinforcing conveyor belts, transmission belts, hoses and more particularly pneumatic hoses and processes and devices for producing them.

 It is known to prepare strands consisting of several son of steel, twisted together the same amount in the same direction. The steel wires used generally have diameters of 0.10 to 0.40 mm and are covered with a thin layer of brass. In order to have the required mechanical properties, in particular sufficient fatigue strength, the strands must have a minimum torsion which for the diameters above is of the order of 50 to 60 revolutions / meter. Cables consisting of an assembly of strands are also prepared with a pitching twist, generally less than the twisting twist. These strands and cables have the disadvantage of not allowing the rubber to penetrate into the core of the product, which leads, when there are cuts in the tires, corrosion of the steel wires by moisture.

 It is known from US Pat. No. 3,273,978 to prepare hollow targets consisting of several filaments previously deformed in helices out of phase with each other, and to hold the wires together by a wrapping thread; this product has the advantage of allowing a good penetration of the rubber between all the wires but it has the defect to have an important lengthening of construction (weak modulus under weak constraints) which makes it poorly adapted for the reinforcement in the belt of the tires and others by the threads touching by points, he has a bad resistance to fatigue by attrition.

It is also known from US patents
Nos. 4,022,009 and 4,030,248 to make cables consisting of at least two bundles of filaments deformed into helices, the filaments remaining parallel to each other in each bundle; a beam may consist of a wire or several son these strands have compared to those mentioned above the advantages of having only a small construction length and to have a good fatigue behavior, but there is the defect conventional strands cited first, to constitute groups of son in which the rubber does not run and thus present channels that allow moisture to walk in case of tire cuts.

 We have just found a type of product that combines a high modulus under low stress, good fatigue resistance, good penetration of rubber between the threads, and therefore increased resistance to corrosion.

 It is a wire cable consisting of at least two elements each having a helical deformation of the same direction and the same pitch, about an axis outside their axis and assembled by nesting in each other propellers thus formed, one being in the hands of the elements being a multi-wire bundle composed of wires of identical or different diameters characterized in that at least one of the multi-wire bundles has a twist on itself such that the pitch of the helix is greater than 50 times the diameter of the largest yarn used in its composition.

 Preferably if the target has multiple multi-wire beams, they are all twisted on themselves.

 For ease of editing, we will call strands or twisted multifilaments on themselves.

 The fact that the strand (s) have a twist on themselves makes it possible not always to present to the eraser the same group of threads and thus to have a rubber penetration around all the strands or strands along the cabal .

 The total number of unitary son constituting the product may be from 3 to 50, preferably from 3 to 10, the diameter of which is preferably between 0.10 and 0.40 mm. The wires may be of identical or different diameters.

 When the strand or strands are each made of son of identical diameters, the pitch of the twist on themselves is preferably between 100 and 500 times the diameter of the son.

 In the present invention, the helix formed by the group of at least two assembled elements has a pitch which may be from 5 to 25 mm, and more generally from 8.7 to 16 mm; the direction of torsion can be indifferently S or Z. The constituent strand or strands can be twisted on themselves from 2 to 50 revolutions / meter (not from 500 to 20 mm) and more generally from 10 to 30 revolutions / meter indifferently in the S or Z direction without relation to the twist direction of the finished cable. These definitions will be illustrated by the examples cited which are not limiting in nature.

 An "open" target is obtained which allows good penetration of the rubber between the threads, in particular due to the low twist on themselves of the strands. However, this twist does not affect the mechanical properties of the target. The mechanical properties related to torsion, such as fatigue, depend only on the torsion of assembly of the constituent elements (nesting of the propellers).

 The present invention also relates to a method of manufacturing the above targets.

 It is a method characterized by the fact that several threads are simultaneously unwound and twisted together at the unwinding to form a first element having a twist around its axis; said first element then being assembled with at least a second element by mutual torsion of the elements with each other, giving each element helical deformation around an axis outside its own axis, at least the first element retaining after assembly a degree of torsion around its axis.

 The assembly of at least the two elements can be done by simple torsion, double twist, or by means implementing the false twist.

 The present invention also relates to types of machines adapted for the manufacture of the products according to the invention. In the following descriptions, a torsion spindle is a set of mechanical members that assembles several threads by twisting the assembly on itself.

It is a machine comprising at least the following elements considered in combination - a first means of unwinding and assembling by torsion for
several threads that make up the first element of the target - a second way of unwinding at least a second element
filiform; - a torsion pin for the assembly of the two elements, the
speed of said spindle and the speed of the unwinding means of the
first element being such that the first element retains a
degree of torsion about its axis after assembly - means for receiving the target.

We will distinguish
Machines type A: machines with false twist assembly: one of the strands can come from an assembly of parallel wires of the same coil or from independent coils located outside the torsion pin, the other strand coming from a spool within the spindle or twisted by appropriate means, the target being flown out of the spindle; or a wire unwound from the outside of the torsion spindle is assembled with a twisted strand also outside the spindle as before, assembly and winding take place inside the torsion spindle.

 Type A machines are shown schematically in Figures 1, 2, 3, 4, 5, 6 and 9.

 In FIG. 1, the coils 1 and 2 carry assemblies of non-twisted filaments, the reel 2 is unwound while giving a twist to the assembly 20 from 2 to 50 revolutions / meter. At the false twist spindle 9 the strand 20 obtained passes in the axis of the spool 1 and is then deviated from the spindle to come together with the assembly 10 (which may be a single filament) with a twist of 40 to 200 turns / master. The target 3 thus obtained is drawn by any usual means shown diagrammatically in FIG. 1 by two capstan rollers 4; it is then drawn, as is already known for metal targets, by a false-twist wringer and / or peelers 5 so that it no longer has a torsion reaction and is then sent to a receiver coil 6.

 In FIG. 2, it can be seen that the twist of the strand 20 can be obtained by simple torsion as is known from independent coils 7 mounted on a turntable 8.

The false twist assembly pin and the traction and finishing means of the target being identical to those shown in FIG.

 In FIGS. 3 and 9 it is shown that the twisting of the strand 20 can be given simply by the coronal reeling system 16, the false assembly twist pin and the means for pulling and finishing the target being identical to those shown on FIG. Figure 1.

 In FIG. 4, it is shown that the twist of the strand 20 can be given by a double twist spindle 11.

 In FIG. 5, it is shown that the twist of the strand 20 can be alternated S, Z, S, etc., this alternating torsion being given by a false twist system 9.

 In Figure 6, the coils carrying the constituent filaments are outside the false twist pin 9 and the receiving coil 6 inside the pin 9. In this case the coil 1 carries only one filament. The strand 20 can be obtained by one of the five means described in Examples 1, 2, 3, 4 and 5 and is twisted from 1 to 50 revolutions / meter. The strand 20 enters the axis of the spindle 9, then is deviated from the axis on a guide secured to the turntable 12 and returns in the axis of the machine to assemble with the monofilament 10. The target 3 and twisted is pulled by a capstan system 4 and then returned to a spool 6 inside the spindle. The cited systems of known wringers and / or blockers can be inserted before or after the capstan to correct the torsional reaction of the product.

Machine type B: machines with single or double twist assembly.

They are characterized by a set of single or double twisted or single and double twisted spindles rotating at different speeds so as to obtain a cable where the constituent strands keep or regain a low twist on themselves (2 to 50 turns /metre). one of the strands can be reduced to a monofilament and it is not necessary that it be twisted on itself: it can then be directly unwound from a reel. One or more strands may have been twisted by the amount necessary to maintain or revert to a small twist in a prior operation, although this means is less economical than with the machines made up of associated pins previously mentioned.

 To illustrate these machines there is shown in Figure 7 an assembly consisting of three double twist spindles; the first 13 carrying 4 coils of monofilaments which are twisted on oux themselves at nltours / meter (in S in the figure); the second pin 14 carries 2 coils of monofilaments which are twisted on themselves at n2 turns / meter (also in S in the figure); the winding spindle 15 assembles the two strands (in Z in the figure) B n3 turns / meter: this last operation detents each of the constituent strands of n3 turns / meter and the residual torsion on each of them is nl - n3 and n2 - n3 in S or Z depending on the respective values of n1, n2 and n3. According to the present invention n1 - n3 and n2 - n3 are between 2 and 50 revolutions / meter, n3 being between 40 and 200 revolutions / meter.

 In FIG. 8, there is shown one of the strands reduced to a monofilament 10 and thus unwinding itself without any torsion other than that possibly due to its unwinding mode16 (unwound reeling, without torsion, could equally well have been represent). The second spindle 17 carrying three coils is a single twist spindle which assembles the three threads A n2 turns @ meter (in S in the figure) the twin spindle winding spindle 18 assembles the strand 20 and the monofilament 10 A n3 turns / meter (in Z in the figure). 3 of three filaments of n3 turns / meter. On the finished product, the three-wire strand will have a residual twist of n2-n3 in S or Z according to the respective values of n2 and n3 and according to the invention n2-n3 will be between 2 and 50 revolutions / meter.

 In each of the embodiments according to FIGS. 7 and 8, it is possible to introduce bodies known in themselves from false twisting and / or dressing, suitable for canceling the torsion reaction of the fihal product.

 Double twist spool pins and single twist spooling spindles may also be associated with the present invention provided that the relationships between n1, n2, n3 as defined for the resulting product are respected.

 Finally, only the assemblies of 2 strands, or 1 monofilament and one strand, are represented in the embodiment examples below, but the product may consist of more than 2 strands and at this moment the machines will have to include the number of strands. corresponding pins.

 The choice of the type of machine particularly adapted depends on the desired end product (number of strands, residual torsions on the strands, torsion of the cable) but also of the desired productivity in relation to the necessary investment.

 The products obtained according to the definition of the present invention will be better illustrated by the following examples which are only exemplary.

 The properties of the products will be discussed later compared to those of the previously known products.

Example 1
On the turntable of a type A machine (FIG. 1), a spool carrying a parallel assembly of 4 brass-coated steel wires of diameter 0.25 mm and in the false-twist spindle a coil carrying a steel monofilament. brass with a diameter of 0.25 mm.

 The assembly is unwound by a coronel giving a twist S of about 2 turns / meter, and the turntable gives a twist 2 of 30 turns / meter.

 In the false twist spindle, the monofilament and the strand are assembled in S at the rate of 80 turns / meter (12.5 mm pitch), then the cable obtained is pulled by the capstan, twisted by a false twister to cancel its reaction, and erected by passage between small rollers before being sent on a reel.

 The resulting product consists of the helical winding of the monofilament and the strand which keeps a twist on itself of 30-228 rpm, that is to say / no twist equal to 140 times the diameter of the yarns. unit.

Example 2
On the fixed plate of a double twisted spindle of the type shown diagrammatically in FIG. 4 is a coil carrying an assembly of 3 brass steel wires of diameter 0.22 mm (or three independent coils of monofilaments). In the type 1 false-twist spindle, an assembly coil of 2 parallel wires of the same diameter is placed.

 The double twist spindle gives the assembly 20 a torsion of 10 turns / meter in S.

 The false twist spindle assembles between them the wick of 2 parallel threads and the strand at 115 revolutions / meter (pitch of 8.7 ;;) in S. In the finished product the strand retains a twist of 10 turns / meter or a step equal to 454 times the diameter of the single wires.

Example 3
An assembly coil consisting of 4 parallel wires with a diameter of 0.28 mm is placed on a single twisted spindle as shown diagrammatically in FIG. 6. A 0.35 mm diameter monofilament spool is available which unwinds on the spool. unrolled from the other side of the machine.

 The monofilament is twisted on itself by the torsion pin å 200 turns / meter in the S direction.

 This 4-wire strand is twisted by 20 turns / meter by the single Z-twisted spindle.

The false-twist assembly gives a twisted monofilament and strand wire together at 100 turn 6 / mb (10mm pitch) in S. The strand retains in the finished product a twist of the individual unit wires of 20 turns / meter in Z , that is to say with a step equal to 175 times the diameter
Example 4
In a type B machine shown schematically in Figure 7, is placed in the cradle of the first strand use double twist reel 4 spools of brass steel wire diameter 0.22 mm (we can also place 'me assembly coil consisting of 4 parallel wires); this pin twists the four wires by 150 turns / meter in S.

 In the cradle of the second double-strand twist-stripping machine, two coils of 0.25 m diameter steel wire (or an assembly coil of 2 parallel wires) are placed; this pin twists the two wires 100 turns / meter in S.

 The two strands are assembled and twisted in double twist by the third spindle double twisting spindle with 115 revolutions / meter Z (not 8.7 mm).

 The final product consists of two strands respectively having 35 revolutions / meter in S and 15 revolutions / meter in Z, respectively a pitch equal to 127 times and 266 times the diameter of the single wires. The two strands are twisted with each other by 115 revolutions / meter in Z.

Example 5
In a machine of the type B shown diagrammatically in FIG. 8, three coils of 0.25 mm diameter brass-plated steel wire are placed on the single-twist spindle: this spindle twists the three wires by 50 turns / meter in S.

 A spool of brass wire 0.25 mm in diameter is placed on a fixed support and the wire is unwound by a coronel.

 The filament and the strand are assembled and twisted by the double winding twist of 80 turns / meter (not 12.5 ws) in Z.

 The resulting product consists of a wire and a strand, twisted together by 80 turns / meter, the strand being twisted on itself by 30 turns / meter in Z, that is to say with a step equal to 133 times the diameter of the single wires.

Compared properties of products

(a) <SEP> (b)
<tb> Adhesion <SEP> in <SEP> a <SEP> rubber
Torsion <SEP> Twist <SEP> Load <SEP> Fati- <SEP> bunch <SEP> A
<tb> of <SEP> of <SEP> ruptu- <SEP> gue <SEP> 3
<tb> after <SEP> after <SEP> aged
Constructions <SEP> cable <SEP> strands <SEP> re <SEP> rou- <SEP> sement
<tb> vulca (t / m) <SEP> (t / m) <SEP> (daN) <SEP> leaux <SEP> nisa- <SEP> in <SEP> under <SEP> in
<tb> meaning <SEP> meaning <SEP> (kc) <SEP> tion <SEP> water <SEP> va- <SEP> atmos
<tb> (b) <SEP> sali- <SEP> fear <SEP> phere
<tb> (daN) <SEP> no <SEP> water <SEP> wet
<tb> (c) <SEP> (d) <SEP> (e)
<tb> (daN) <SEP> (daN) <SEP> (noted /
<tb> 10)
<tb> Cable <SEP> (1 + 3) <SEP> 0.25 <SEP> 80 <SEP> S <SEP> 28 <SEP> Z <SEP> 50 <SEP> 6.0 <SEP> 45 <SEP > 42 <SEP> 37 <SEP> 9
<tb> according to <SEP> (2 + 2) <SEP> 0.25 <SEP> 100 <SEP> S <SEP> 20Z / 20 <SEP> Z <SEP> 53 <SEP> 6.3 <SEP> 48 <SEP> 47 <SEP> 42 <SEP> 9.5
<tb> the invention <SEP> (2 + 3) <SEP> 0.22 <SEP> 115 <SEP> S <SEP> 0/10 <SEP> S <SEP> 53 <SEP> 7.2 <SEP> 49 <SEP> 50 <SEP> 41 <SEP> 8
<tb> tion <SEP> (1x0.35) + (4x0.28) <SEP> 100 <SEP> S <SEP> 0/20 <SEP> Z <SEP> 62 <SEP> 3.2 <SEP> 52 <SEP> 49 <SEP> 38 <SEP> 9
<tb> (2x0.25) + (4x0.22) <SEP> 115 <SEP> Z <SEP> 15Z / 35 <SEP> S <SEP> 65 <SEP> 6.1 <SEQ> 48 <SEP> 46 <SEP> 36 <SEP> 9
<tb> 4x0.25 <SEP> 80 <SEP> S <SEP> - <SEP> 51 <SEP> 5.5 <SEP> 43 <SEP> 36 <SEP> 25 <SEP> 4
<tb> Products
<tb> 5x0.22 <SEP> 115 <SEP> S <SEP> - <SEP> 55 <SEP> 6.6 <SEP> 45 <SEP> 32 <SEP> 20 <SEP> 3.5
<tb> usual <SEP> 5x0,25 <SEP> 80 <SEP> S <SEP> - <SEP> 59 <SEP> 5,0 <SEP> 50 <SEP> 39 <SEP> 31 <SEP> 1
<tb> a) SODETAL machine: Vulcanized specimen with placed cable
under a voltage corresponding to 10% of the breaking load
passing between three rollers at a frequency of 750 c / min. b) Test specimen according to ASTM D2229.

(c) The vulcanized specimen is kept submerged at half height
for 3 days in a solution of NaCl at 50 g / l.

d) The vulcanized specimen is maintained for 8 hours 120 C under
pressure of 2 bars of water vapor.

(e) The unvulcanized 30x100x3 mm test tube with strands
every 1.5 mm is held for 12 days at 250c and 75% humidity.
relative humidity, then vulcanized and peeled
the layer of rubber to discover the cables: we note the
7. recovery of gum remaining on the strands (noted on 10).

 It will be noted that the tensile strengths and the fatigue strength are substantially the same as for conventional constructions involving the same number of filaments. Likewise the initial adhesion, before aging, retains substantially the same values.

 On the other hand, we see the interest of the constructions claimed in the aging tests: the new constructions are perfectly penetrated by the gum and the humidity does not degrade the adhesion very little. The central duct, which is not filled with rubber of conventional constructions, allows moisture to flow and rapidly spreading the loss of adhesion and corrosion.

 The present invention is applicable to strands and wire ropes for reinforcing elastomeric objects, and in particular steel wire targets for reinforcing tires.

Claims (16)

REVENDICATI0s  1 / - Target metal son consisting of at least two elements each having a helical deformation of the same direction and the same not around an axis outside their own axis and assembled by nesting into each other helices thus formed, l at least one of the elements being a multi-wire bundle composed of wires of identical or different diameters, characterized in that at least one of the multi-bundles  son presents a twist on himself such as the heel step  lice is greater than 50 times the diameter of the largest wire in  trant in its composition.  2 / - Cabal according to claim 1 wherein each multifil element is made of son of identical diameters, characterized in that the pitch of the helix of the multi-wire element or elements is between 100 and 500 times the diameter of the single son.  3 / - Target according to one of claims 1 and 2 wherein the son constituting a diameter of between 0.10 and 0.40 ", characterized in that the multifilaments twisted on themselves have a twist included between 2 and 50 revolutions / meter and preferably between 10 and 30 revolutions / meter.  4 / - Cable according to one of claims 1 to 4, charac terized in that the total number of son constituting the cable is between 3 and 50 and preferably between 3 and 10.  5 / - Target according to one of claims 3 and 4, characterized in that the assembly step of its elements cons  are between 5 and 25 mm and preferably between 8.7  and 16 mm.  6 / - Target according to one of claims 1 to 5, carac  characterized in that it is constituted by at least one unitary wire and a multi-wire bundle.  7 / - Target according to one of claims 1 to 5, carac  characterized in that it is constituted by at least two multi-wire beams.  8 / - A method of manufacturing a cable according to one of claims 1 to 7, characterized in that it turns simultaneously several son, which is assembled by torsion to the dump to form a first member having a torsion about its axis, said first member then being assembled with at least a second member by mutual torsion of the elements with each other, giving each element helicoidal deformation around an outer axis i its own axis, at least the first element retaining after assembly a degree of torsion about its axis.  9 / - Method according to claim 8, characterized in that the assembly of at least the two elements is effected by simple torsion.  10 / - Method according to claim 8, characterized in that the assembly of at least the two elements is carried out by double-torsion.  11 / - Method according to claim 8, characterized in that the assembly of at least the two elements is effected by means implementing the false twist.  12 / - Machine for manufacturing the target according to one of claims 1 to 8, characterized in that it comprises in combination at least the following elements - a first means of unwinding and assembly by torsion for several son who constltuent the first element of the target, - a second means for the unwinding of at least a second filamentary element, - a torsion pin for the assembly of the two elements, the speed of said spindle and the speed of the unwinding means the first element being such that the first element retains a degree of torsion about its axis after assembly, means for receiving the target.  13 / - Machine according to claim 12, characterized in that the torsion pin is a false-torsion pin.  14 / - Machine according to claim 12, characterized in that the torsion pin is a double-torsica pin.  15 / - Machine according to claim 12, characterized in that the torsion pin is a single-torsion pin.  161 - Hachine according to one of claims 12 i 15, characterized in that the first unwinding means is conè- titué by a rotary plate carrying one or more feed coils.  17 / - Machine according to one of claims 12 to 15, characterized in that the first unwinding means is con-titué by a double-torsion pin.  18 / - Machine according to one of claims 12 w 15, characterized in that the first unwinding means is aghast by a coronel associated with a fixed supply coil.  19 / - Machine according to claim 13, characterized in that the second unwinding means is constituted by a coil and a coronel located in the false-torsion pin.  201 - Machine according to claim 14, characterized in that the second unwinding means is a doubletorsion pin.  21 / - Machine according to claim 14, characterized in that the second unwinding means is a turntable carrying at least one feed reel.  221 - Machine according to claim 14, characterized in that the second unwinding means is a coronelle assignee of a fixed feed reel.