US20070089394A1 - Fine steel cord with a low structural elongation - Google Patents

Fine steel cord with a low structural elongation Download PDF

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Publication number
US20070089394A1
US20070089394A1 US10/577,995 US57799504A US2007089394A1 US 20070089394 A1 US20070089394 A1 US 20070089394A1 US 57799504 A US57799504 A US 57799504A US 2007089394 A1 US2007089394 A1 US 2007089394A1
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Prior art keywords
cord
fine steel
steel cord
load
elongation
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US10/577,995
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Stijn Vancompernolle
Paul Bruyneel
Bert Vanderbeken
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Bekaert NV SA
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Bekaert NV SA
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Assigned to N.V. BEKAERT S.A. reassignment N.V. BEKAERT S.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BRUYNEEL, PAUL, VANDERBEKEN, BERT, VANCOMPERNOLLE, STIJN
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    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B1/00—Constructional features of ropes or cables
    • D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core
    • D07B1/0693—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core having a strand configuration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
    • F16G1/00—Driving-belts
    • F16G1/28—Driving-belts with a contact surface of special shape, e.g. toothed
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B1/00—Constructional features of ropes or cables
    • D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core
    • D07B1/0606—Reinforcing cords for rubber or plastic articles
    • D07B1/0613—Reinforcing cords for rubber or plastic articles the reinforcing cords being characterised by the rope configuration
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B3/00—General-purpose machines or apparatus for producing twisted ropes or cables from component strands of the same or different material
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/10—Rope or cable structures
    • D07B2201/104—Rope or cable structures twisted
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/20—Rope or cable components
    • D07B2201/2015—Strands
    • D07B2201/2042—Strands characterised by a coating
    • D07B2201/2044—Strands characterised by a coating comprising polymers
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2205/00—Rope or cable materials
    • D07B2205/20—Organic high polymers
    • D07B2205/2064—Polyurethane resins
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2207/00—Rope or cable making machines
    • D07B2207/20—Type of machine
    • D07B2207/207—Sequential double twisting devices
    • D07B2207/208—Sequential double twisting devices characterised by at least partially unwinding the twist of the upstream double twisting step
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2401/00—Aspects related to the problem to be solved or advantage
    • D07B2401/20—Aspects related to the problem to be solved or advantage related to ropes or cables
    • D07B2401/2005—Elongation or elasticity
    • D07B2401/201—Elongation or elasticity regarding structural elongation
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2401/00—Aspects related to the problem to be solved or advantage
    • D07B2401/20—Aspects related to the problem to be solved or advantage related to ropes or cables
    • D07B2401/202—Environmental resistance
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2501/00—Application field
    • D07B2501/20—Application field related to ropes or cables
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2501/00—Application field
    • D07B2501/20—Application field related to ropes or cables
    • D07B2501/2076—Power transmissions

Definitions

  • the invention relates to a fine steel cord for reinforcing a synchronous belt.
  • Synchronous belts have found their way in many precision machines; in automobiles, in computer peripheral apparatus such as printers and copying machines, in positioning systems and in many other applications. In the art they are also known under other names such as ‘toothed belts’, ‘transmission belts’ or ‘timing belts’. In what follows, the terms and definitions according the standard ISO 5288-1982 will be adhered to. Industry standards DIN 7721-1989 and ISO 5296-1: 1989 define the sizes and tolerances of commercially available synchronous belts. Synchronous belts are applied where power transmission or precise longitudinal continuous or stepped displacement of the belt or precise angular positioning over a longer distance is of the essence.
  • One of the main requirements posed to a synchronous belt is the tolerance on the pitch length (see ISO 5288 for the definition), which on its turn determines the tooth pitch.
  • the pitch length tolerance varies from ⁇ 0.28 mm on a pitch length of 100 mm (0.28%) to ⁇ 1.46 mm on a pitch length of 3620 mm (or 0.04%, see DIN 7721).
  • the tolerances as set forth by the DIN 7721 standard are not longer sufficient as uses of synchronous belts are spanning longer distances or require better precision control.
  • the fitting between belt tooth and gear wheel has to remain very precise during the use of the belt.
  • the above mentioned tolerances only apply for unused synchronous belts. Any misfit during engagement of the tooth into the gear recess will lead to premature wear of the belt or even teeth jumping out of the gear. The problem of ‘dimensional control’ has thus emerged for synchronous belts.
  • Multistrand cords were widely used in the past for the reinforcement of radial tires.
  • Load-elongation diagrams of all multistrand cords known in the art do not show a linear elastic behaviour from the start of the curve onward: there is a small offset of the linear part attributed to the (re) arrangement of filaments and strands in the cord upon loading or unloading. This offset is called ‘structural elongation’ (see infra) and is never smaller than 0.090%. It is found that this ‘structural elongation’ is even more pronounced when using finer filaments to make the multistrand cord.
  • Multistrand cords are made in a two-step process.
  • filaments are twisted to a strand with a particular lay length and direction onto a strand spool.
  • a second step a number of strands are pulled-off from the strand spools and twisted to a cord with a specified lay length and direction.
  • Either one or both of the twisting steps can be performed in a cabling machine or alternatively in a bunching machine. In the art, the latter technology is preferred due to its higher twisting speed and due to the larger spools that it allows for.
  • the cord is of the sZ type—or its' mirror image the zS type—and the cord is twisted in a bunching machine
  • account has to be taken for the number of twists that are taken out of the strand by the bunching operation. If we denominate the number of twists of the strands per unit length of finished cord by N c and the number of twists of the filaments per unit length of strand in the finished cord as N s then the strands have to be twisted up to N s +N c twists in order to end with N s twists per unit length of the strand in the final cord.
  • the inventors have found a different solution to solve the ‘dimensional control problem’ of synchronous belts, which is a first object of the invention. Surprisingly their solution also solved the ‘curling’ and ‘sabre’ effect. In addition their solution also increased the overall modulus of the cord in the working region of the belt thus reducing the elongation of the belt between loaded and unloaded part of a belt cycle without having to use more reinforcement material: a second object of the invention. The inventors have found a method to produce the multi strand cords in an efficient way: a third object of this invention.
  • the invention relates to the combination of features as described in claim 1 .
  • Specific features for preferred embodiments of the invention are set out in the dependent claims 2 to 6 and 10 to 13 .
  • the invented method is comprised by the combination of features as described in claim 7 .
  • Specific features of preferred methods are in claims 8 and 9 .
  • the use of the fine steel cord as a reinforcement for synchronous belts is claimed in claim 14 .
  • a fine steel cord for reinforcing a synchronous belt is claimed.
  • Plain carbon steel is preferably used.
  • Such a steel generally comprises a minimum carbon content of 0.40 wt % C or at least 0.70 wt % C but most preferably at least 0.80 wt % C with a maximum of 1.1 wt % C, a manganese content ranging from 0.10 to 0.90 wt % Mn, the sulfur and phosphorous contents are each preferably kept below 0.03 wt %; additional micro-alloying elements such as chromium (up to 0.2 to 0.4 wt %), boron, cobalt, nickel, vanadium—a non-exhaustive enumeration—may also be added.
  • stainless steels contain a minimum of 12 wt % Cr and a substantial amount of nickel. More preferred are austenitic stainless steels, which lend themselves more to cold forming. The most preferred compositions are known in the art as AISI (American Iron and Steel Institute) 302, AISI 301, AISI 304 and AISI 316.
  • AISI American Iron and Steel Institute
  • the fine steel cord comprises at least two strands, each of said strands comprising at least two steel filaments.
  • the filaments have dimensions ranging between 30 ⁇ m and 250 ⁇ m but most preferred are sizes between 40 and 175 ⁇ m.
  • the most preferred filament size is between 120 to 160 ⁇ m. As these filaments are relatively thin compared to tire cord filaments, the cords resulting from them are therefore called ‘fine’.
  • the filaments used can be without any coating.
  • the wires can be coated with a suitable coating. Preferred are:
  • the latter coating type is most preferred.
  • Other coating types such as zinc alloy coatings e.g. a zinc aluminium alloy (e.g. having an eutectoid composition of about 95 wt % zinc and about 5 wt % Al) or even ternary alloys are not excluded. It should be clear that the enumeration of coating types is non-exhaustive.
  • the filaments are twisted together with a certain lay direction and a lay length.
  • the lay length is from 10 to 40 times the diameter of the strand. More preferred is a lay length between 20 to 30 times the diameter of the strand.
  • the strands are twisted together to a cord having a lay length of between 5 to 20 times the diameter of the cord. More preferred is a lay length between 7 and 14 times the diameter of the cord.
  • cord combinations known in the art, which are envisaged in this invention, as long as they are composed out of at least two strands possibly, wound or not wound around a core.
  • the cords according the invention have strands with a lay direction opposite to the lay direction of the cord. E.g. if the strands have a lay direction in S, the cord will have a lay direction Z.
  • FIG. 1 The features of the load-elongation curve that are of importance to understand the invention are illustrated in FIG. 1 .
  • the fine cords that are object of this invention show a very distinct load-elongation behaviour compared to state-of-the-art fine cords. This behaviour can be best distinguished by subjecting the cords to a cyclic loading between a low load and a high load.
  • a ‘low’ load is e.g. the load used during manufacturing of the belt: 10 to 50 N is customary.
  • a ‘high’ load is e.g. the load on the cord during use of the belt in the loaded part of a belt cycle.
  • Belts are normally subjected to a maximum of 20 to 30% of their nominal breaking load.
  • the load-elongation curves are taken over different cycles between the low and high load, the reason being to be able to distinguish between the phenomenon of the ‘setting of the cord’ ( FIG. 1 , ‘A’) and the ‘structural elongation’ ( FIG. 1 , ‘B’).
  • the ‘setting of the cord’ is a first time adjustment of the filament positions leading to a small permanent elongation. After the first loading this ‘setting of the cord’ has disappeared.
  • ‘Structural elongation’ remains after repeated loading. Typically 20 cycles are used in order to ascertain that the cord has fully settled although in practice the curve does not alter anymore after about 10 cycles.
  • the cyclic load—elongation diagram shows hysteresis i.e. the loading and unloading curve do not coincide completely and form a dosed loop (‘H’ in FIG. 1 ). Therefore it is here understood that the structural elongation must be defined on the return cycle i.e. in going from 20% of the breaking load to 0.2% of the breaking load.
  • Fine steel cords according the invention have a structural elongation below 0.09 % (claim 1 ) and preferably below 0.06% (claim 2 ).
  • a further characteristic of the invention is that the load-elongation curve below 20% of the breaking load does not show the non-linear curve as is typical for the state-of-the-art cords.
  • the elongation behaviour of the cord at loads below 20% of its breaking load fairly accurately follows a linear Hooke's law.
  • the load-elongation curve of the invention cords remains between two straight lines that are separated by an elongation of 0.06% thus confining the load-elongation curve in a straight band.
  • the load-elongation curves remain in this band from the second cycle onward—i.e. excluding the ‘setting of the cord’—up to the twentieth cycle.
  • the slope exhibited by this band is markedly different from that of the prior art cords. If we consider the slope between the lower—i.e. the turning point at 0.2% of the breaking load—and upper turning point—i.e. the turning point at 20% of the breaking load—divided by the metallic surface of the wires as an ‘equivalent elongation modulus’ (as illustrated by the slope of line ‘G’ in FIG. 1 ), the invention cords have an equivalent elongation modulus exceeding 150 000 MPa (claim 4 ) and more preferably exceeding 170 000 MPa (claim 5 ). This is already much closer to the theoretical achievable maximum of about 200 000 MPa for a single wire. This equivalent elongation modulus is also known as the secant modulus between defined forces (see K. Feyrer, “Drahtseil, 2. Auflage”, page 81)
  • the ‘setting of the cord’ can be conveniently quantified as the elongation at first cycle, the cycle comprising: pre-tensioning the cord at 0.2% of its breaking load, loading the cord to 20% of its breaking load followed by unloading the cord to 0.2% of its breaking load.
  • the elongation then measured is the ‘setting elongation’ (see ‘A’ of FIG. 1 ). It will be clear to the person skilled in the art that ‘the setting of the cord’ can only be determined on cords that have not been loaded before. This setting elongation remains below 0.03% for the invention cords.
  • the fine steel cord can also be coated with an elastomer coating (claim 10 ).
  • this coating encloses a single fine steel cord and is round and thin.
  • the elastomer is by preference polyurethane as this is the material normally used to make timing belts and is therefore compatible (claim 11 ).
  • Such a coating must adhere well to the fine steel cord in order to maintain the integrity of the composite during use (claim 12 ).
  • Adherence of the cord to the elastomer can be assessed through the ASTM 2229/93 pull-out test.
  • the pull-out force of the fine cord—having a diameter ‘D’ expressed in mm—embedded in an elastomer over a length ‘L’ must be larger than 40 ⁇ D ⁇ L Newton, but most preferred is if the elastomer adheres to the cord with a pull-out force that is larger than 50 ⁇ D ⁇ L Newton.
  • the penetration of the elastomer greatly helps to keep the filaments ‘in place’ during their use. It is therefore preferred that the elastomer penetrates at least the outer strands of the cord. Most preferred is that all individual filaments are completely surrounded by polymer over substantially the length of the fine cord (claim 13 ).
  • the inventors have also observed another unexpected advantage of the inventive cord: the spread of all parameters—and most notably the structural elongation—in the load-elongation curve is lower for the inventive cords compared to the spread for the conventional cords.
  • ‘Spread’ in this context has to be considered as the long-term variation from production run to production run. The reduced variation can easily be understood from the fact that a structural elongation below zero is simply not possible.
  • the inventive cords are ‘calibrated’ against the theoretical cord having a zero structural elongation. As such they will have a much lower spread compared to conventional cords where in the latter the structural elongation can wander in both directions.
  • the second aspect of the invention concerns a method to produce the inventive cord.
  • the needed strands are produced having a number of twists n s of at the most N s i.e. the number of twists the filaments must have in the strand of the final cord.
  • Each of the necessary strand spools is mounted in an individual twister pay-off.
  • a twister pay-off is a pay-off system that is able to increase the number of twists per unit length in the strand when turning in the same lay direction of the strand.
  • the twister pay-off is able to reduce the number of twists per unit length of the strands when it is turning in the direction opposite to the lay direction of the strand.
  • the number of twists added or subtracted is proportional to the ratio of rotational speed of the twister to the linear speed of the strand.
  • the rotational speed is adjustable. Most preferable is that both speeds are adjustable.
  • All strands are lead to the assembly point at the entrance of a bunching machine.
  • There the strands are assembled into a cord.
  • the strands obtain N c twists per unit length.
  • the strands are untwisted with N c twists per unit length.
  • the rotational speed of the twister pay-off must be adapted in order to obtain the correct number of twists per unit length of the strand in the final cord.
  • the cord is wound on a cord spool at the inside of the bunching machine.
  • the inventors have found that in order to obtain the fine cords as claimed, the number of twists per unit length that a strand locally obtains along its track from strand spool to cord spool must be minimal, i.e. definitely below N c +N s and preferably close to N s , while even below N s before entry in the cord is not excluded. Any excess of twists given to the strands—even if these twists are finally taken out of the strand upon bunching of the cord—leads to ‘looseness’ of the strands, which is reflected in the undesired structural elongation, causing the dimensional control problem of the synchronous belts.
  • the pay-off tension is most conveniently expressed in terms of the ultimate breaking load of the strand. At least the pay-off tension must be higher than 15% of the strand's breaking load. Preferably it is above 20%.
  • a torque is exerted on the strand that therefore tends to untwist and thereby starts to rotate during its travel from strand spool to cord spool. Due to this rotation, the total number of twists of the strand before entry into the cord is lowered.
  • a second important feature of the method is that the entrance pulley of the bunching machine must be put under an angle with respect to the plane formed by entering and exiting cord (claim 8 ). After this pulley the cord is guided in a bow towards the reversing pulley at the end of the bow. Preferentially these pulleys are grooved. Even more preferred is that these pulleys have a U shaped grove larger than the diameter of the cord. Normally the rotational axis of the entrance pulley is perpendicular to the plane formed by entering an exiting cord i.e. directed along the normal of that plane. According to the invention the entrance pulley axis is inclined with respect to this normal.
  • the inclination is set such that the cord rolls in the U shaped groove in its closing direction.
  • the closing direction is the rotational direction in which the number of twists on the cord increases. More preferred is that the axis of the pulley is rotated around the bisector of the lines formed by the entering and exiting cord. Even more preferred is that both entrance and reversing pulley are put under an angle (claim 8 ). The principle of putting the entrance and reversing pulleys under angle is to shift the point where the strands in the cord obtain their final number of twists to the assembly point. In this way the untwisting of the strands in the bow of the bunching machine is prevented.
  • a third feature of the invented method relates to the path the strand travels from strand spool to cord spool.
  • the path must not be obstructed by any type of guiding pieces, rollers, pulleys or any other device that could impede the rotation of the strand. Any of such devices leads to a restriction of the untwisting by the bunching machine, which should be prevented according the invention (claim 9 ).
  • FIG. 1 Depicts a typical load-elongation of a fine steel cord, with the parameters of importance.
  • FIG. 2 Shows the load elongation diagram of a fine steel cord of type 7 ⁇ 3 ⁇ 0.15 according the prior art and according a first preferred embodiment.
  • FIG. 3 Shows the load elongation diagram of a fine steel cord of type 3 ⁇ 3 ⁇ 0.15 according the prior art and according a second preferred embodiment.
  • FIG. 4 a Illustrates the prior art production method and the inventive production method.
  • FIG. 4 b Illustrates the variation of twists per unit length on the strand in their travel from strand spool to cord spool for both the state-of-the-art method ‘CP’ and inventive method ‘IP’.
  • FIG. 5 a drawing of a pulley mountable under angle.
  • the inventors have produced a 7 ⁇ 3 type of cord characterised by the following formula: [(3 ⁇ 0.15) 9 s +6 ⁇ (3 ⁇ 0.15) 9 s ] 8 Z i.e. a core strand consisting of 3 filaments twisted together with a lay length of 9 mm in S direction is combined with 6 outer strands again consisting of 3 filaments twisted together with a lay length of 9 mm in S direction to a cord.
  • the strands are twisted in to the cord with a lay length of 8 mm in Z direction.
  • the filaments were plain carbon steel filaments having a carbon content of about 0.725 wt. % C and having a hot dip galvanised zinc coating.
  • the cord was produced from the filaments according the conventional process and the inventive process.
  • the cord has a metal cross-sectional area of 0.371 mm 2 (acc. DIN 3051 i.e. sum of filament cross sections).
  • a strand spool 2 containing a strand with N s twists per meter—is mounted in a twister pay-off system 4 .
  • a twister pay-off 1 as known in the art can be physically implemented by rotatably mounting a spool 2 in a stationary hanging cradle (not shown) suspended between two rotation points (not shown).
  • the strand is pulled form the spool through the first rotational point over a revolving reversing pulley or guide piece 4 to the second rotational point where again a revolving reversing pulley or guide piece 5 leads the strand out of the twister pay-off in a direction opposite to the direction in which the strand is pulled form its spool.
  • the strand maybe guided through a flyer 3 rotating around the stationary cradle.
  • flyer 3 rotating around the stationary cradle.
  • embodiments without flyer 3 are also known in the art.
  • twister pay-off Other embodiments of a twister pay-off are known in which the spool rotation axis on its turn rotates around an axis along which the strand leaves the pay-off, the latter axis being perpendicular to the spool rotation axis. Also these embodiments of a twister pay-off are explicitly included in the inventive process.
  • the twister pay-off will add to N s a number of twists per meter.
  • the added number of twists must correspond to the number of twists of the cord N c , because the bunching machine 13 will later remove exactly this number of twists.
  • the dashed line between P0 and P2 in FIG. 4 b schematically depicts the increase of the number of twists per unit length of the strand.
  • the strand After leaving the twister pay-off at P2 ( FIG. 4 a ), the strand is guided over different guiding pulleys 6 such that the strand can conveniently be combined with other strands 7 to form the cord in the assembly point 8 .
  • an individual twister pay-off For each strand, an individual twister pay-off must be operated under identical process conditions.
  • the strands are twisted together by the bunching machine 13 .
  • the cord receives N c twists per meter while the strands are untwisted N c twists per meter.
  • N c /2 twists are taken out of the strands between entrance pulley 9 and reversing pulley 10 and the remaining N c /2 twists are taken out from the strands between the reversing pulley 10 and cord spool 12 .
  • the evolution of the number of twists on the strand is illustrated by the dashed line between P4 and P6 of FIG. 4 b.
  • N s is (1000/9) twists per meter and N c is (1000/8) twists per meter.
  • the strands will be untwisted in their travel from strand spool to cord spool and this must be compensated for by twisting up to (1000/9)+(1000/8) twists per meter, which corresponds to a lay length of 4.235 mm in ‘s’ direction.
  • FIG. 4 b (the dashed line marked ‘CP’) illustrates the evolution of the number of twists per meter on the strand in its travel from strand spool to cord spool in the conventional process. It will be clear that the tight twisting of 4.235 mm leaves a helical plastic deformation in the strands when they are untwisted to a lay length of 9 mm. This helical plastic deformation leads to the high structural elongation.
  • FIG. 4 b illustrates the difference on the number of applied twists per unit length on the strand for the conventional process (curve ‘CP’) and the inventive process (curve ‘IP’).
  • the number of twists n s of the original strands is lower or equal than N s in the inventive process as indicated in P0 of FIG. 4 b . Due to this, the twister pay-off must run at a higher rotational speed than the bunching machine in order to get the correct number of twists per unit length in the strands of the final cord.
  • twists applied are physically prevented of building up to a local level of N s +N c by applying a higher pay-off tension to the strands than in the conventional process.
  • a torque develops in the strand that untwists the strands, thus reducing the number of twists on curve ‘IP’ in P2 of FIG. 4 b to well below N s +N c .
  • a further improvement to allow the free rotation of the strand is the elimination of the guiding pulleys 6 in FIG. 4 a .
  • Guiding pulleys have the tendency to restrict the rotation of strands as soon as they bend the cord. Because some pulleys have been eliminated the strand twists also do not built up at P3 as shown on curve ‘IP’ in FIG. 4 b , P3.
  • Another improvement to limit the built-up of twists in the strand is to bring the strand untwisting action of the bunching machine closer to the assembly point 8 .
  • This can be achieved by putting the entrance and/or reversing pulley 9 of the bunching machine under an angle as illustrated in FIG. 5 .
  • There the entering cord 51 is guided over a U grooved pulley 56 and leaves as exiting cord 52 .
  • the bisector of the entering cord 51 and exiting cord 52 that is perpendicular to the plane of the paper is noted as 55 .
  • the axis of the pulley 54 is rotated over the angle ⁇ with respect to the normal to the plane 53 formed by entering cord 1 and exiting cord 2 .
  • the direction of the angle should be chosen such that the cord tends to dose.
  • FIG. 2 the identification of the different features as discussed for FIG. 1 are used. Added also is a strip ‘J’ having a width of 0.06% in elongation, illustrating the fact the invention cord remains in between these limits (claim 3 ).
  • a second preferred embodiment is a 3 ⁇ 3 ⁇ 0.15 cord of which the table 3 both summarises the processing conditions used and product features obtained.
  • the load-elongation curve can be found in FIG. 3 .
  • the 3 ⁇ 3 ⁇ 0.15 construction is constructed as follows: [3 ⁇ (3 ⁇ 0.15) 9 s ] 8 z
  • a third preferred embodiment concerns a (3+5 ⁇ 7) ⁇ 0.15 fine steel cord that can be detailed as follows: [(3 ⁇ 0.15) 9 s +5 ⁇ (0.15+6 ⁇ 0.15) 10 s ] 12.5 z
  • the cord was manufactured according the standard and the inventive process and the following results were obtained: TABLE 4 Parameter Conventional process Inventive process Cord Breaking Load 1730 N (*) 1730 N (*) Low load limit 3.46 N 3.46 N High load limit 346 N 346 N Structural elongation on 0.085% 0.023% return of 20th cycle Slope equivalent to an 142 000 N/mm 2 173 000 N/mm 2 elongation modulus Elongation after 1 st cycle 0.006% 0.0085% (*) aim value, not measured.
  • the 7 ⁇ 3 ⁇ 0.15 of the first embodiment was coated with an elastomer coating.
  • the cord Prior to this coating, the cord was cleaned by means of a steam degreasing step. Subsequently the cord was dipped into a solution of 1.5 vol. % of N-(2-amino ethyl)-3-amino propyl tri methoxy silane dissolved in a mixture of isopropanol and water, followed by drying.
  • organo functional silanes for adhesion promotion is known in the art (see e.g. WO 2004/076327).
  • the cord was coated with a layer of Desmopan®392 from Bayer, enlarging the bare cord diameter from 0.90 mm to 1.00 mm. Coating was performed by means of a standard extruder whereby the steel cord was preheated to 180° C. prior to entering the extruder head. Polyurethane was injected into the extruder head at 225° C. at a pressure of 100 bar. After coating the coated fine steel cord was cooled in water.
  • a cross section of the cord revealed that each of the 21 filaments was embedded in PU.
  • a closed loop belt was produced with a 10 mm pitch and a length of 840 mm containing 16 cords of type 7 ⁇ 3 ⁇ 0.15.
  • a first belt was produced with conventional process (CP) cords, a second belt was produced with the inventive process (IP) cords, and a third belt was made with IP cords, coated with PU.
  • the belts had a breaking load of about 15 kN. They were cyclically loaded 10 times from a pretension of 100 N (‘Low Load’) to 5 kN (‘High Load’). Although the measuring conditions are not exactly the same as for the cords, a comparison of the relevant parameters can still be made.
  • the belts with the IP cords and the coated IP cords showed a much lower elongation and—consequently—tooth wear than the CP cords. This proves that the inventive cord solves the ‘dimensional control’ problem.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Ropes Or Cables (AREA)
  • Laminated Bodies (AREA)
  • Tires In General (AREA)
US10/577,995 2003-11-03 2004-10-15 Fine steel cord with a low structural elongation Abandoned US20070089394A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP03104053.8 2003-11-03
EP03104053 2003-11-03
PCT/EP2004/052557 WO2005043003A1 (en) 2003-11-03 2004-10-15 Fine steel cord with a low structural elongation

Publications (1)

Publication Number Publication Date
US20070089394A1 true US20070089394A1 (en) 2007-04-26

Family

ID=34530784

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/577,995 Abandoned US20070089394A1 (en) 2003-11-03 2004-10-15 Fine steel cord with a low structural elongation

Country Status (10)

Country Link
US (1) US20070089394A1 (de)
EP (1) EP1680610B1 (de)
KR (2) KR101184642B1 (de)
CN (1) CN100523542C (de)
AT (1) ATE437318T1 (de)
DE (1) DE602004022188D1 (de)
ES (1) ES2328248T3 (de)
PL (1) PL1680610T3 (de)
SI (1) SI1680610T1 (de)
WO (1) WO2005043003A1 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100009184A1 (en) * 2007-01-08 2010-01-14 Nv Bekaert Sa Cable with low structural elongation
US20100119806A1 (en) * 2005-07-20 2010-05-13 Nv Bekaert Sa Roll of preformed steel cord reinforced strip
JP2018506659A (ja) * 2015-02-19 2018-03-08 コンパニー ゼネラール デ エタブリッスマン ミシュラン タイヤの保護補強材のための１×ｎ構造のマルチストランドケーブル
US20180229415A1 (en) * 2015-07-30 2018-08-16 Habasit Ag System and method for manufacturing flightless, monolithic belt

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10647539B2 (en) * 2015-02-09 2020-05-12 Nv Bekaert Sa Tension buffer system for multi-wire pay-off system
CN110799701B (zh) 2017-06-27 2022-11-11 贝卡尔特先进帘线阿尔特公司 用于增强聚合物制品的增强股
EP3645442B1 (de) 2017-06-27 2024-05-22 Bekaert Advanced Cords Aalter NV Mit stahlsträngen verstärkter riemen
DE102019217625A1 (de) * 2019-11-15 2021-05-20 Contitech Antriebssysteme Gmbh Aufzugsgurt mit Corden aus beschichteten Litzen

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US3522139A (en) * 1967-08-03 1970-07-28 Dunlop Co Ltd Reinforced rubber or plastic article
US3600884A (en) * 1968-07-09 1971-08-24 Bridgestone Tire Co Ltd Steel cord for reinforcing rubber articles
US3911662A (en) * 1973-01-22 1975-10-14 Nat Standard Co Steel tire cords, method of making same and articles containing same
US4087295A (en) * 1972-02-25 1978-05-02 Monsanto Company Mechanical and thermal treatment of steel wire
US4106957A (en) * 1971-09-02 1978-08-15 N. V. Bekaert S.A. Reinforcements
US4123894A (en) * 1977-08-05 1978-11-07 Bethlehem Steel Corporation Sealed wire rope
US4602476A (en) * 1984-12-03 1986-07-29 Amsted Industries Incorporated Plastic filled wire rope with strand spacer
US4878343A (en) * 1983-05-16 1989-11-07 Akzo Bm Arnhem, The Netherlands Reinforcing rope made of at least two different materials
US5464510A (en) * 1993-07-21 1995-11-07 Dynamotive Corporation Method for removal of certain oxide films from metal surfaces
US5784874A (en) * 1996-06-03 1998-07-28 N.V. Bekaert S.A. Multi-strand cord for timing belts
US5843583A (en) * 1996-02-15 1998-12-01 N.V. Bekaert S.A. Cord with high non-structural elongation
US6206907B1 (en) * 1999-05-07 2001-03-27 Cardia, Inc. Occlusion device with stranded wire support arms
US20020150786A1 (en) * 1997-07-29 2002-10-17 D'haene Urbain Steel cord for protection plies of pneumatic tires

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JPH0768673B2 (ja) * 1991-12-27 1995-07-26 トクセン工業株式会社 ゴム製品補強用スチールコード
JP3777210B2 (ja) * 1995-01-24 2006-05-24 横浜ゴム株式会社 空気入りラジアルタイヤ
KR100276014B1 (ko) * 1998-12-15 2000-12-15 조충환 공기입타이어용고강도스틸코드
DE60016582T2 (de) * 1999-12-27 2005-05-25 Fuji Seiko Co. Ltd. Herstellungsvorrichtung für einen gummibeschichteten strang

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US3509710A (en) * 1966-10-07 1970-05-05 Dunlop Co Ltd Reinforced rubber articles
US3522139A (en) * 1967-08-03 1970-07-28 Dunlop Co Ltd Reinforced rubber or plastic article
US3600884A (en) * 1968-07-09 1971-08-24 Bridgestone Tire Co Ltd Steel cord for reinforcing rubber articles
US4106957A (en) * 1971-09-02 1978-08-15 N. V. Bekaert S.A. Reinforcements
US4087295A (en) * 1972-02-25 1978-05-02 Monsanto Company Mechanical and thermal treatment of steel wire
US3911662A (en) * 1973-01-22 1975-10-14 Nat Standard Co Steel tire cords, method of making same and articles containing same
US4123894A (en) * 1977-08-05 1978-11-07 Bethlehem Steel Corporation Sealed wire rope
US4878343A (en) * 1983-05-16 1989-11-07 Akzo Bm Arnhem, The Netherlands Reinforcing rope made of at least two different materials
US4602476A (en) * 1984-12-03 1986-07-29 Amsted Industries Incorporated Plastic filled wire rope with strand spacer
US5464510A (en) * 1993-07-21 1995-11-07 Dynamotive Corporation Method for removal of certain oxide films from metal surfaces
US5843583A (en) * 1996-02-15 1998-12-01 N.V. Bekaert S.A. Cord with high non-structural elongation
US5784874A (en) * 1996-06-03 1998-07-28 N.V. Bekaert S.A. Multi-strand cord for timing belts
US20020150786A1 (en) * 1997-07-29 2002-10-17 D'haene Urbain Steel cord for protection plies of pneumatic tires
US6475636B1 (en) * 1997-07-29 2002-11-05 N.V. Bekaert S.A. Steel cord for protection plies of pneumatic tires
US6206907B1 (en) * 1999-05-07 2001-03-27 Cardia, Inc. Occlusion device with stranded wire support arms

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100119806A1 (en) * 2005-07-20 2010-05-13 Nv Bekaert Sa Roll of preformed steel cord reinforced strip
US7846539B2 (en) * 2005-07-20 2010-12-07 Nv Bekaert Sa Roll of preformed steel cord reinforced strip
US20100009184A1 (en) * 2007-01-08 2010-01-14 Nv Bekaert Sa Cable with low structural elongation
JP2018506659A (ja) * 2015-02-19 2018-03-08 コンパニー ゼネラール デ エタブリッスマン ミシュラン タイヤの保護補強材のための１×ｎ構造のマルチストランドケーブル
US20180229415A1 (en) * 2015-07-30 2018-08-16 Habasit Ag System and method for manufacturing flightless, monolithic belt

Also Published As

Publication number Publication date
KR101182725B1 (ko) 2012-09-13
CN1875205A (zh) 2006-12-06
KR20060101482A (ko) 2006-09-25
SI1680610T1 (sl) 2009-10-31
KR101184642B1 (ko) 2012-09-20
DE602004022188D1 (de) 2009-09-03
EP1680610A1 (de) 2006-07-19
ATE437318T1 (de) 2009-08-15
CN100523542C (zh) 2009-08-05
KR20120049342A (ko) 2012-05-16
EP1680610B1 (de) 2009-07-22
ES2328248T3 (es) 2009-11-11
WO2005043003A1 (en) 2005-05-12
PL1680610T3 (pl) 2009-12-31

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