Coated wire rope

Abstract

 A wire rope well suited for application to an elevator or a cargo handling machine, in which each of side strands (2) is constructed by twisting ordinary linear members together with at least one resinous linear member (4) that is larger in diameter than each of the ordinary linear members. Owing to the existence of the resinous linear member (4) of the relatively larger diameter, gaps (S2,S1) are respectively defined between the individual side stands (2) and a core rope (1) and between the respectively adjacent side strands (2), and a resin for outer layer coating (3) is pressed and packed through the gaps (S2,S1), thereby to prevent wear ascribable to the touch between a core rope (1) and the outer side strands (2), as well as wear ascribable to the touch between the adjacent outer side strands (2), and wear ascribable to the metal touch between a sheave and the outer side strands (2).

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a coated wire rope which is well suited mainly for the running ropes of an elevator, a cargo handling machine, etc.

BACKGROUND OF THE INVENTION

[0002] A running rope for use in an elevator or a cargo handling machine represented by crane is moved or taken up via a sheave, and is therefore subject to severe conditions under which tensions and bendings act over the full length of the rope.

[0003] Heretofore, such a running rope has had a structure wherein, as stipulated in JIS·G·3525 or 3546, etc., a plurality of side strands are arranged and twisted together round the outer periphery of a core rope which is made of a stranded rope of fiber or steel.

[0004] With this structure, however, high surface pressures act on the core rope and the side strands, and the frictions between the core rope and the side strands occur due to the bending of the rope by the sheave or the like. When the diameter of the rope decreases due to the consequent abrasion of the core rope, the surface pressures between the adjacent side strands increase still more. This has resulted in the problem that each strand wears away, or that individual wires constituting the core rope and the side strands break.

[0005] Known as a countermeasure is a running rope wherein a thermoplastic resin layer is interposed between the core rope and each of the side strands. According to this prior art, the metallic touch between the core rope and each side strand is prevented, but appropriate intervals are difficult to be held among the individual side strands. Therefore, the individual side strands are liable to touch with one another and to wear away. Another problem is that the sheave and the side strands slide relative to each other in continuous metal touch, so the sheave being relatively soft wears away to expend much labor and a long time on the replacement of the expensive sheave. Besides, when the running rope is oiled in order to diminish the wear, the coefficient of friction between the sheave and the rope changes, and a slip arises between the sheave and the rope, so that the rotation of the sheave becomes difficult to be accurately transmitted to the rope. This has resulted in the problem that the precision of the position control of an object connected to the rope (for example, an elevator cage or a cargo to be handled) lowers, or that the use of a sheave subjected to special grooving is necessitated.

SUMMARY OF THE INVENTION

[0006] The present invention has been made in order to eliminate the problems as stated above, and has for its object to provide a coated wire rope which can prevent wear ascribable to the touch between a core rope and the outer side strands, as well as wear ascribable to the touch between the adjacent outer side strands, and wear ascribable to the metal touch between a sheave and the outer side strands, which can realize a favorable frictional touch (driving force transmission) between the sheave and the rope as a whole, and which is easy of fabrication.

[0007] In order to accomplish the object, the coated wire rope of the present invention consists in a coated wire rope characterized by comprising a core rope, a plurality of side strands which are arranged around, and twisted together with, the core rope, and a coating resin layer which covers outer peripheries of the side strands, wherein each of the side strands is constituted by a plurality of linear members twisted together, at least one of which is a resinous linear member having an outside diameter relatively larger than each of the remaining linear members, gaps are respectively defined between the individual side stands and the core rope and between the respectively adjacent side strands owing to existence of the resinous linear member, and the gaps are filled up with portions of a resin for an outer layer coating of the coated wire rope.

[0008] In more detail, the side strands have a circumscribed circle which is formed by the linear members other than the resinous linear members, and a circumscribed circle which is formed by the resinous linear members and whose diameter is relatively larger, and the gaps of substantially equal sizes are defined between the respectively adjacent side strands owing to the circumscribed circle formed by the resinous linear members, while at the same time, the gaps of substantially equal sizes are defined between the individual side stands and the core rope owing to the circumscribed circle formed by the resinous linear members.

[0009] According to such a construction, since each of the side strands includes at least one resinous linear member of relatively larger outside diameter, the resinous linear members of the individual side strands touch the adjacent side strands partly and simultaneously touch the core rope partly, in a state where the side strands are arranged and twisted together around the core rope. Since the linear members other than the resinous linear members are relatively smaller in outside diameter, the gaps being substantially uniform are reliably defined between the respectively adjacent side strands. Moreover, the gaps being substantially uniform are reliably defined between the individual side strands and the core rope.

[0010] Therefore, the outer layer resin covers the outer side of the circumscribed circle joining all the side strands, and besides, it permeates into the regions between the respectively adjacent side strands and the regions between the individual side strands and the core rope. Thus, triangular resin layers which fill up the valleys between the respectively adjacent side strands are formed around the core rope, and they extend radially so as to connect with the outer layer resin.

[0011] Owing to the existence of the resinous linear members, the individual side strands exhibit rugged sections of different shapes, and the resin layers of the resinous linear members adhere with the outer layer resin, so that an excellent integral structure is obtained.

[0012] The resin layers between the adjacent side strands and between the side strands and the core rope function as spacers which serve also as buffer members. Accordingly, wear ascribable to the touch between a core rope and the outer side strands, as well as wear ascribable to the touch between the adjacent outer side strands, can be prevented without requiring oiling, and wear ascribable to the metal touch between a sheave and the outer side strands can be prevented by the resin layer of the outermost layer. At the same time, a favorable relation for transmitting a driving force can be realized between the sheave and the rope as a whole.

[0013] Preferably, the coated wire rope of the present invention is fabricated by the step of preparing a plurality of metallic linear members, and at least one resinous linear member which includes a reinforcement wire portion centrally and which is larger in diameter than each of the metallic linear member, and arranging the metallic linear members and the resinous linear member around either of a central linear member and an inner layer and twisting them together, thereby to form a side strand which has a convex sectional shape owing to the resinous linear member; the step of arranging a plurality of such side strands around a core rope and twisting them together, thereby to fabricate a non-coated rope; and the step of passing the non-coated rope through an extruding machine, pressing and packing a melted resin into regions between the adjacent side strands, and into regions between the individual side strands and the core rope via spaces which are defined between the side strands owing to existence of the resinous linear members, and forming an outer layer which is thick beyond a circle circumscribed to the side strands.

[0014] According to this construction, one coating step suffices, and any resin coating operation need not be performed before the side strands are twisted together with the core rope. Therefore, the fabrication is easy to bring forth the advantage that a productivity can be enhanced.

[0015] Preferably, at least two resinous linear members are included in each of the side strands, and they are arranged at positions spaced from each other on a circumference of the corresponding side strand and are twisted together with the other linear members, thereby to form a guide channel which is similar to a helical groove.

[0016] According to this construction, since each side strand includes the two or more resinous linear members, it can increase the number of points of contact while avoiding the metal touch thereof with the adjacent side strand, and the uniform gaps can be stably defined between the core rope and the side strands and between the adjacent side strands. Moreover, since the helical guide channel is formed on the circumference between the resinous linear members of larger diameter, the permeation and packing of the resin into the regions between the core rope and the outer side strands and into the regions between the adjacent side strands can be smoothly carried out.

[0017] Besides, preferably the resinous linear member includes a central reinforcement wire portion , and a resin layer with which the central reinforcement wire portion is coated, and it has a diameter which is 1.01 - 1.1 times that of each of the other linear members.

[0018] According to this aspect, since the resinous linear member has the diameter which is 1.01 - 1.1 times that of each of the other linear members, the uniform gaps of appropriate sizes suited to the permeation of the resin can be defined without causing any metal touch between the core rope and the side strands or between the individual side strands. Moreover, since each resinous linear member includes the reinforcement wire portion, a strength required for the side strand can be ensured.

[0019] Preferably, the resin layer of the resinous linear member is made of the same material as the resin for the outer layer coating. According to this, the resin of the resinous linear members is softened or melted by the heat of the packed resin for the outer layer coating, and a homogeneous joined state in which adhesion powers, etc. are equal can be formed.

[0020] Preferably, the core rope to be used is one in which a resin coating layer is provided around the rope proper. According to this, the touches between the core rope and the side strands can be reliably prevented, and the core rope can be reliably and integrally joined with the resin for the outer layer coating as has permeated between the side strands.

[0021] Although other aspects and advantages of the present invention will be clarified from the ensuing detailed description, the invention shall not be restricted to constructions disclosed in embodiments, as long as the fundamental features thereof are included. It will be obvious to one in the art that various modifications and alterations are possible without departing from the idea or scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 

Fig. 1 is a perspective view, partially broken away, showing the first aspect of a coated wire rope according to the present invention;

Fig. 2 is an enlarged sectional view corresponding to Fig. 1;

Fig. 3-A is an enlarged and partially broken-away perspective view showing an example of a resinous linear member for use in the present invention;

Fig. 3-B is an enlarged and partially broken-away perspective view showing another example of the resinous linear member for use in the present invention;

Fig. 4-A is an enlarged perspective view of a side strand in the first aspect;

Fig. 4-B is a sectional view corresponding to Fig. 4-A;

Fig. 5 is a sectional view showing the rope of the first aspect in its state before outer layer coating (in its state of a non-coated rope);

Fig. 6-A is an explanatory view showing an outer layer coating step;

Fig. 6-B is an explanatory view schematically showing the permeating state of a resin during the coating step;

Fig. 7-A is a sectional view showing the second aspect of a coated wire rope according to the present invention in its state before outer layer coating (in its state of a non-coated rope);

Fig. 7-B is a sectional view of the rope in the second aspect;

Fig. 8 is a partially broken-away perspective view showing the third aspect of a coated wire rope according to the present invention;

Fig. 9 is an enlarged sectional view corresponding to Fig. 8;

Fig. 10 is an enlarged perspective view of a side strand in the third aspect;

Fig. 11 is a sectional view of the side strand in the third aspect;

Fig. 12 is a sectional view showing the third aspect in its state before the outer layer coating of a rope (in its state of a non-coated rope);

Fig. 13-A is a sectional view showing the fourth aspect of a coated wire rope according to the present invention in its state before the outer layer coating of a rope (in its state of a non-coated rope);

Fig. 13-B is an enlarged sectional view of a side strand in the fourth aspect; and

Fig. 14 is an explanatory view showing a testing jig for the rope of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Now, embodiments of the present invention will be described with reference to the accompanying drawings.

[0024] Fig. 1 through Fig. 6-B show the first aspect of a coated wire rope according to the present invention.

[0025] Referring to Figs. 1 and 2, numeral 1 designates a core rope, which is so constructed that a synthetic resin coating layer 1b is arranged around the core rope proper 1a formed by twisting wires or strands together. Although the structure of the core rope proper 1a may be as desired, this example has a 1 × 7 structure in which six side linear members 102 surrounding a central linear member 101 are twisted together.

[0026] Numerals 2 designate a plurality of (in the illustration, six) side strands which are arranged and twisted together around the core rope 1. Numeral 3 designates an outer layer coating (general coating) of synthetic resin matter which is formed so as to embrace the side strands 2, and which is packed so as to fill up the gaps between the adjacent side strands 2, 2 and the gaps between the individual side strands 2 and the core rope 1.

[0027] More specifically, the outer layer coating 3 includes the filling portion 300 between the adjacent side strands 2, 2, the filling portion 301 between the side strand 2 and the core rope 1, and a cylindrical outer layer portion 302 which lies around and beyond a circle D3 circumscribed to all the side strands 2, 2, ···. The outer layer portion 3 02 is united with the filling portions 301 being inner layers, by the filling portions 300 extending radially. The filling portions 301 are integrally joined with the synthetic resin coating layer 1b of the core rope 1.

[0028] Each of the side strands 2 includes a central linear member (central member) 201, and a plurality of linear members 202 and 4 for side use as surround the central member 201. In this example, as shown in Figs. 4-A and 4-B, the side strand 2 has a 1 × 7 structure in which the six linear members for side use surrounding the central linear member 201 are twisted together.

[0029] The side-use linear members consist of two sorts; the metallic linear members 202, and at least one (in this example, two) resinous linear member 4. The resinous linear member 4 has an outside diameter larger than that of the metallic linear member 202.

[0030] Steel wires are usually employed as the linear members 201, 202. Also, steel wires are employed as the central wire 101 and side wires 102 of the core rope proper 1a. In a case where a high strength is required of the rope, the steel wires to be used have tensile strengths of at least 240 kg/cm². Such a steel wire is obtained by drawing a starting wire rod whose carbon content is 0.70 wt-% or more. Here, the "steel wire" shall cover also one whose surface has a thin anticorrosive coating, for example, zinc plating or zinc - aluminum alloy plating.

[0031] Each resinous linear member 4 may well be generally made of a resin. Since, however, the strand constituted by the resinous linear members 4 is desired to function as a strength member, the resinous linear member 4 should preferably have a composite structure in which, as shown in Fig. 3-A or Fig. 3-B, a reinforcement wire portion 4a is centrally arranged and is surrounded with a resin layer 4b. The resin layer 4b is joined to the reinforcement wire portion 4a. Such a resinous linear member 4 can be continuously obtained by passing the reinforcement wire portion 4a through a melted resin bath so as to stick the resin thereto, and subsequently removing the surplus parts of the resin, or by passing the reinforcement wire portion 4a through the die of a resin extruding machine.

[0032] The reinforcement wire portion 4a may be a single wire as shown in Fig. 3-A, or it may well consist of a plurality of wires 400 twisted together, as shown in Fig. 3-B. A steel wire is usually used for the reinforcement wire portion 4a, but it may well be substituted by a synthetic fiber. The synthetic fiber in this case should preferably be a high-strength and low-ductility fiber which is selected from among aramide, ultrahigh molecular weight polyethylene, entirely aromatic polyester, etc. The reinforcement wire portion 4a is fabricated in such a way that a large number of yarns made of such a fiber are bundled, and that the bundles are drawn up in parallel or laid with a long lead.

[0033] Usable as a resin for forming the resin layer 4b is one which exhibits a good adhesion to the reinforcement wire portion 4a, for example, polyvinyl chloride, nylon, polyester, polyethylene, polypropylene, or any of the copolymers of these resins. From the viewpoint of attaining a favorable adhesion with the resin of the outer layer coating 3, however, the resin of the resin layer 4b should preferably be a thermoplastic resin having the same property as or a close property to that of the resin of the outer layer coating 3.

[0034] Preferable as the resin of the outer layer coating 3 is one which has a suitable elasticity for adjusting the friction coefficient of this outer layer coating with a sheave, in addition to a wear resistance, a weather resistance and a pliability (stress crack resistance), and whose friction coefficient is comparatively high. Therefore, the elastomer of, for example, an acrylic resin, a polyurethanic resin or an etheric polyurethane is employed as the resin of the outer layer coating 3. It is accordingly appropriate to employ the high polymer material for the resin layer 4b. The resin is appropriate also for the core rope coating layer 1b.

[0035] The diameter of the resinous linear member 4 needs to be at least 101 % relative to that of the other linear member 202. The reason therefor is as stated below. When the resinous linear member 4 having a smaller diameter is used for forming the side strand 2, it protrudes out of a circumscribed circle formed by the linear members 202, only very slightly. Accordingly, when the side strands 2 are laid into the rope, a gap which is large enough to assist in the permeation of the resin for the outer layer coating 3 cannot be defined between the adjacent side strands 2, 2.

[0036] The upper limit of the diametral ratio to the linear member 202 is about 110 %. When the diametral ratio is still larger, the resinous linear member 4 becomes difficult to be accommodated between the linear members 202, so that it floats to come out, or the gap defined between the adjacent side strands 2, 2 becomes too large, with the result that a steel filling rate per unit section lowers.

[0037] The diameters of the resin layer 4b and the reinforcement wire portion 4a are selected so as to attain the diametral ratio specified above. Herein, from the viewpoint of causing the reinforcement wire portion 4a to act as the reinforcement member, the diameter of this portion 4a is set to be equal to or appropriately smaller than that of the other sort of linear member 202. In relation to the balance of strengths, and from the viewpoint of lowering a cost by decreasing the number of the sorts of wire rods for use, it is more preferable to equalize the diameter of the portion 4a to that of the linear member 202.

[0038] In the case where the plurality of resinous linear members 4 are included, they are arranged at positions spaced from each other on a circumference, preferably at symmetrical positions on the circumference, and they are twisted together with the other linear members 202 at a predetermined pitch.

[0039] Accordingly, in a state where the resinous linear members 4 are twisted together, they become helical in the lengthwise direction of the side strand 2 as shown in Fig. 4-A. Since the resinous linear members 4 are larger in diameter relative to the other linear members 202, the side strand 2 becomes a shape in which, as shown in Fig. 4-B, a circle D2 circumscribed to the resinous linear members 4 surrounds the circumscribed circle D1 formed by the ordinary linear members 202.

[0040] When a plurality of such side strands 2 are arranged and twisted together around the core rope 1, a non-coated rope A as shown in Fig. 5 is obtained. The laying direction of each strand 2 and that of the rope 1 should preferably be opposite to each other. By way of example, when the laying direction of the strand 2 is the direction of the left hand lay, that of the rope 1 is set to be the direction of the right hand lay.

[0041] Incidentally, the positions of the resinous linear members 4 on the circumstances of the individual side strands 2, 2 should preferably be random as exemplified in Fig. 5. This is also convenient from the viewpoint of facilitating the fabrication of the rope.

[0042] In such a non-coated rope A, suitable gaps S1 are substantially uniformly defined between the adjacent side strands 2, 2 owing to the circumscribed circles D2 of the helical resinous linear members 4, while at the same time, suitable gaps S2 are substantially uniformly defined between the side strands 2 and the core rope 1 owing to the circumscribed circles D2 of the helical resinous linear members 4.

[0043] The non-coated rope A is washed under this state and is entirely preheated to about 100 °C, whereupon it is subjected to an operation for forming the outer layer coating 3. Usually, the operation is continuously performed in such a way that, as shown in Fig. 6-A, the non-coated rope A is passed through the die 90 of an extruding machine 9 which extrudes a melted resin 30 under pressure.

[0044] During the coating extrusion, as shown in Fig. 6-B, the melted resin 30 is pressed and packed into the uniform gaps S1 defined between the adjacent side strands 2, 2, and it is packed into the gaps S2 defined between the side strands 2 and the core rope 1 and leading to the gaps S1, whereby the gaps S1 and S2 are filled up.

[0045] As seen from Fig. 4-A, a guide channel similar to a helical groove is formed between the resinous linear members 4, 4 of the larger diameter. Along the guide channels, therefore, the melted resin 30 can be smoothly and reliably poured into the gaps between the side strands 2 and the core rope 1 and packed into the gaps between the adjacent side strands 2. From this fact, and the point that the number of contacts of each side strand with the adjacent side strand increases to stabilize the gap defined between these side strands, the number of the resinous linear members 4 of each side strand 2 should preferably be two or more.

[0046] The resinous linear members 4 in the individual side strands 2, 2 have been preheated as described above, and they are heated in touch with the melted resin 30 of high temperature in this state, so that at least the surfaces of the resin layers 4b are made sticky or melted. In the latter case where the surfaces of the resin layers 4b are melted, also the melted resin components permeate through the gaps S1 and the gaps S2 until they fuse with the coating layer 1b of the core rope 1. That is, the resinous linear members 4 serve also as part of the melted resin for coating and effect the function of replenishing the resin from within the rope.

[0047] As shown in Fig. 2, accordingly, the radial permeant resin layers 300 each of which resembles a triangle filling up the valley between the adjacent side strands 2, 2 can be reliably formed between the individual side strands 2, 2, while the permeant resin layers 301 which are respectively joined with the permeant resin layers 300 and which are ring-shaped as a whole can be similarly formed between the side strands 2 and the core rope 1.

[0048] The melted resin 30 finally covers all the side strands 2. Herein, since the side strands 2 coexist with the thicker resinous linear members 4, they are in complicated sectional shapes having large adhesion surface areas and being rugged, and the resin layers 4b adhere or fuse with the melted resin 30 in such a state. Accordingly, the adhering powers between the side strands 2 and the inner parts of the cylindrical outer layer 302 finished up so as to surround the side strands 2 are high to enlarge resistances to shifts.

[0049] Moreover, the outer layer 302 is integrally joined with the ring-shaped permeant resin layers 301 between the side strands 2 and the core rope 1, owing to the radial permeant resin layers 300 which are formed between the side strands 2, 2 and each of which resembles the inverted triangle filling up the valley between the adjacent side strands 2, 2.

[0050] In a case where the resin layer 1b of the core rope 1, the resin layer 4b of the resinous linear member 4 of each side strand 2, and the outer layer resin layer 3 are of the same material, they are easily fused by applying heat, and the physical and chemical properties of the resin within the section of the rope are homogeneous. Therefore, the coatings are less liable to rupture or shift due to the frictional force or shearing force of the rope with the sheave.

[0051] The present invention defines the gaps between the respectively adjacent side strands 2, 2 and between the side strands 2 and the core rope 1 in such a way that the resinous linear members 4 coexist as the linear members which constitute the outer layers of the side strands 2. Therefore, the step of resin-coating each whole side strand 2 beforehand is dispensed with, and the resin coating operation of the side strands 2 can be implemented during the coating of the whole rope. Accordingly, one coating step suffices, thereby to realize a high productivity and a low cost.

[0052] Furthermore, in a case where, unlike the present invention, the side strands 2 are coated with a resin beforehand and are twisted together with a coated core rope, the resulting structure being wholly coated with the resin, the resin is difficult of permeating into the regions between the cylindrical coated side strands and the cylindrical coated core rope, and voids might appear to spoil the integral formation of the side strands and the core rope. In contrast, the present invention eliminates such apprehension. Besides, since the steel material filling rate can be heightened, the rope can be made favorable in strength.

[0053] When the thickness of the outer layer 302 from the outside diameter (circumscribed circle D3) of the side strands 2 is too small, the rope is scanty of durability, and its lifetime ascribable to wear shortens. However, when the thickness is too large, a pliability required of the running rope is spoilt, and the diameter of the rope enlarges to lower a strength efficiency. Therefore, it is usually preferable to set the thickness at 1/5 of the rope diameter or less, for example, at about 0.3 - 2.0 mm.

[0054] Figs. 7-A and 7-B show the second aspect of the present invention. In this example, three of linear members forming the outer layer of each side strand 2 are resinous linear members 4, and the three resinous linear members 4 are arranged at equal intervals. Only one of the side strands 2 is illustrated in detail, and the other side strands 2 are simplified in illustration. Since the remaining construction of the rope is the same as in the first embodiment, identical portions shall be denoted by identical numerals and signs and omitted from description.

[0055] In the present invention, the construction of the core rope 1 and that of each side strand 2 are not especially restricted. Fig. 8 through Fig. 12 show another aspect (the third aspect) of the present invention. Herein, the core rope proper 1a of the core rope 1 is constituted by IWRCs of 7 × 7, which are surrounded with a resin coating layer 1b.

[0056] The side strands 2 are constructed of 8 × S (17 +2) structures. More specifically, the central member of each side strand 2 is formed of an inner layer 2a in which nine fine linear members 203 are arranged around a thick central linear member 201', and seven linear members 201 made of steel and at least one resinous linear member 4 (in the illustration, two members) are arranged and twisted together as an outer layer around the inner layer 2a. The resinous linear members 4 are arranged between the three linear members and the four linear members. The construction of each resinous linear member 4 and the diametral ratio thereof relative to the steel wire, a resin to be used, the conditions of an outer layer coating, the functions of a fabricated rope, etc. are all the same as in the first embodiment, the description of which shall therefore apply.

[0057] Figs. 13-A and 13-B show an example which uses three resinous linear members 4, and in which the resinous linear members 4 are arranged at intervals of two steel wires 201. The remaining construction is the same as in the first embodiment, the description of which shall therefore apply.

EXAMPLES

[0058] A coated rope was fabricated by applying the present invention. A core rope had a construction in which the core rope proper of 1 × 7 structure was coated with an etheric polyurethane (Shore hardness: D scale 90), and it had an outside diameter of 3.0 mm. Besides, six side strands each having a 1 × 7 structure were arranged and twisted together around the core rope.

[0059] Each side strand was such that four of six linear members forming an outer layer were steel wires, while the remaining two were resinous linear members. Each of the steel wires used had a diameter of 1.00 mm, while each of the resinous linear members used had a construction in which the steel wire having the diameter of 1.00 mm was coated with the etheric polyurethane (Shore hardness: D scale 90) by an extruding machine, and it had a diameter of 1.1 mm. The resinous linear members were arranged among the steel wires, and the resinous linear members and the steel wires were laid in the S direction and twisted together at a pitch of 30 mm, whereby the side strand was obtained.

[0060] The side strands of the above specifications were prepared in the number of 6, and they were arranged around the core rope and twisted together in the Z direction at a lay pitch of 80 mm, whereby a non-coated rope was fabricated.

[0061] When the non-coated rope was tested, gaps each being of 0.2 mm were uniformly provided between the individual side strands, and gaps each being of 0.1 mm were formed between the core rope and the side strands.

[0062] After washing, the non-coated rope was preheated to 100 °C, and it was coated with the etheric polyurethane (Shore hardness: D scale 90) melted at 200 °C, by the extruding machine, whereby a coated rope whose outer layer D3 had a thickness of 1.0 mm and whose outside diameter was 11 mm was obtained.

[0063] The coated rope was cut, and was observed with a microscope. Then, it was confirmed that the coating resin completely filled up the regions between the respectively adjacent side strands and also the regions between the side strands and the core rope, and that the coating resin was integral with the outer layer resin.

[0064] Regarding the coated rope obtained, the adhesion degree between an outer layer coating 3 and the non-coated rope A was tested in such a way that the coating 3 and the rope A were pulled in opposite directions by a jig as shown in Fig. 14. For the sake of comparison, an adhesion degree test was also conducted as to a rope in which all the outer layer wires of each side strand were steel wires without including any resinous linear member. As a result, it was confirmed that the rope of the present invention increased the adhesion degree by about 80 % as compared with the rope which employed no resinous linear member. When resin filling rates were measured by observation with the microscope, it was confirmed that the rope of the present invention increased the resin filling rate by about 65 % as compared with the rope which employed no resinous linear member.

[0065] Besides, the numbers of times of the occurrence of abnormalities in the coating resin were investigated by conducting S bending tests under the conditions of a D (sheave diameter)/d (rope diameter) ratio of 20, a safety factor of 10, and the use of a round groove sheave. As a result, a coating shift occurred at 50000 cycles in the rope employing no resinous linear member, whereas no abnormality occurred even at 150000 cycles in the rope of the present invention.

[0066] By the way, in a case where the number of resinous linear members was changed and where the single resinous linear member was employed, it was confirmed that the rope of the present invention increased the adhesion power between the outer layer coating and the non-coated rope, by about 50 % as compared with the rope employing no resinous linear member. Besides, a resin filling rate within the rope was observed to increase by 40 % in the case of the single resinous linear member, and by 80 % in case of three resinous linear members.

[0067] Regarding the number of times of the occurrence of abnormalities in the coating resin, no abnormality occurred at 100000 cycles even in the case of the single resinous linear member.

POSSIBILITY OF INDUSTRIAL USE

[0068] Although the present invention is well suited for application to a running rope, it is also applicable to standing ropes such as the hanger rope of a suspension bridge, and the cable and stay of a long skew bridge. In the applications to these uses, a coating resin surrounds side strands, and besides, the resin fills up the regions between a core rope and the side strands, via the regions between the respectively adjacent side strands, so as to bring the core rope and the side strands into firm and integral adhesion, so that the appearance of any void between the coated articles and the rope proper, attributed to the difference of the expansion coefficients of steel and the resin, can be avoided to effectively prevent corrosion ascribable to water (including water due to dew condensation).

Claims

1. A coated wire rope comprising a core rope (1), a plurality of side strands (2) which are arranged around, and twisted together with, said core rope (1), and a coating resin layer (3) which covers outer peripheries of said side strands (2), wherein each of said side strands (2) is constituted by a plurality of linear members twisted together, at least one of which is a resinous linear member (4) having an outside diameter relatively larger than each of the remaining linear members, gaps (S1), (S2) are respectively defined between the individual side stands (2) and said core rope (1) and between the respectively adjacent side strands(2), (2) owing to existence of said resinous linear member (4), and the gaps are filled up with portions (300), (301) of a resin for an outer layer coating of said coated wire rope.

2. A coated wire rope according to claim 1, wherein said side strands (2) have a circumscribed circle (D1) which is formed by the linear members other than the resinous linear members (4), and a circumscribed circle (D2) which is formed by said resinous linear members (4) and whose diameter is relatively larger, and the gaps (S1) of substantially equal sizes are defined between said respectively adjacent side strands owing to the circumscribed circle (D2) formed by said resinous linear members (4), while at the same time, the gaps (S2) of substantially equal sizes are defined between said individual side stands (2) and said core rope (1) owing to said circumscribed circle (D2).

3. A coated wire rope according to claim 1, wherein at least two resinous linear members (4) are included in each of said side strands (2), and they are arranged at positions spaced from each other on a circumference of the corresponding side strand (2) and are twisted together with the other linear members (202), thereby to form a guide channel which is similar to a helical groove.

4. A coated wire rope according to claim 1, wherein said resinous linear member (4) includes a central reinforcement wire portion (4a), and a resin layer (4b) with which said central reinforcement wire portion (4a) is coated, and it has a diameter which is 1.01 - 1.1 times that of each of the other linear members (202).

5. A coated wire rope according to claim 4, wherein said resin layer (4b) of said resinous linear member (4) is made of the same material as the resin for the outer layer coating.

6. A coated wire rope according to claim 1, wherein said core rope (1) includes a resin coating layer (1b) around the rope proper (1a).

7. A coated wire rope according to claim 1, wherein said coated wire rope is for use in either of an elevator and a cargo handling machine.

8. A method of fabricating a coated wire rope, comprising:

1) the step of preparing a plurality of metallic linear members, and at least one resinous linear member which includes a reinforcement wire portion centrally and which is larger in diameter than each of the metallic linear member, and arranging the metallic linear members and the resinous linear member around either of a central linear member and an inner layer and twisting them together, thereby to form a side strand which has a convex sectional shape owing to the resinous linear member;

2) the step of arranging a plurality of such side strands around a core rope and twisting them together, thereby to fabricate a non-coated rope; and

3) the step of passing the non-coated rope through an extruding machine, pressing and packing a melted synthetic resin into regions between the adjacent side strands, and into regions between the individual side strands and the core rope via spaces which are defined between the side strands owing to existence of the resinous linear members, and forming an outer layer which is thick beyond a circle circumscribed to the side strands.

Drawing