CA1163879A

CA1163879A - Wire rope

Info

Publication number: CA1163879A
Application number: CA000393000A
Authority: CA
Inventors: Tatsuo Yoshida; Akihiko Tomiguchi; Kikuo Fukuda
Original assignee: Shinko Wire Co Ltd
Current assignee: Kobelco Wire Co Ltd
Priority date: 1980-12-27
Filing date: 1981-12-22
Publication date: 1984-03-20
Also published as: ZA818253B; AU526489B2; DE3149783A1; KR830008074A; JPS57121684A; KR870000476B1; DE3149783C2; JPS6346196B2; AU7793481A

Abstract

ABSTRACT OF THE DISCLOSURE
A wire rope which includes a filler material disposed in the interstices between a core rope and respective outer strands and/or in the gaps between individual outer strands wherein the filler element is placed independently in the respective interstices and gaps or and interstice and an outwardly contiguous strand gap as an independent unit. A reinforcing core is anchored in the filler element at least in the interstices between the core rope and the respective outer strands.

Description

1 ~63~79 BACKGROUND OF THE INVENTION
_ Field of the Invention This invention relates to a filler-laid wire rope.
Descripti~n of the Prio~ Art In the fabrication of a w~re core rope, it is known in the art to fill the gaps between the individual outer strands with a filler material like a thermoplastic resin or to impregnate a filler material into all the gaps and interstices including the gaps between the core rope and the outer strands as disclosed in U.S. Patent No. 3,824,777. Such impregnated wire ropes possess excellent properties in abrasive resistance, fati-gue strength and loss of wire rope breaking load by stranding and closing, due to the effects of suppressing abrasive contact of the individual outer strands or of the outer strands with the core rope and entrapping the lubricant oil impregnated into the core rope and strands. However, the conventional impregnated wire rope which has the filler material integrally positioned around its entire outer periphery has an inherent drawback in that the flexibility of the wire rope as a whole is impaired to a considerable degree. Further, the filler material is susceptible to cracking and peeling especially when the rope is used as a running rope.
SUMMAR~ OF THE INVENTION
- . . .
Therefore, the present invention has as its object the provisi~n for a wire rope which does not invite deterioration in flexibility and prevents cracking and peeling of the filler material, while retaining the fundamental effects with regard to the higher abrasive resistance and fatigue strength and reduction of loss of wire rope breaking load by stranding and closing.
One feature of the wire rope according to the present ~ ~63~79 1 invention resides in the fact that, in filling a filler material in the interstices between the core rope and the respective outer strands and/or in the gaps between the individual outer strands, a filler element is placed independently in the respective inter-stices and gaps qr an interstice and an outwardly contiguous strand gap are treated ~s an independent unit.
Another feature of the invention resides in the fact that a reinforcing core is anchored in the filler element at least in the interstices between the core rope and the respective outer strands.
~RIEF DESCRIPTION OF THE DRAWINGS
Various other objects, features and attendant advan-tages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connnection with the accompanying drawinys in which like reference characters designate like or corresponding parts through the several views and wherein:
Fig. 1 is an enlarged sectional view o a wire rope in accordance with a first embodiment in the present invention;
Fig. 2 is a fragmentary perspective view of a filler element;
Fig. 3 is a schematic view showing filler elements of different sectional shapes;
Fig. 4 shows an apparatus for producing the wire rope of the present invention;
Fig. 5 is an enlarged sectional view taken along line V-V of Fig. 4;
Fig. 6 is an enlarged view showing a wire rope con-struction in accordance with a second embodiment, Fig. 7 is a fragmentary perspective view of the filler elements used in the second embodiment;

1 ~63~79 1 Fig. 8 is an enlarged section~l view.showing a third embodiment o$ the present invention; and Fig. 9 is a fragmentary perspective view of the filler elements us.ed in the third embodiment.
DETAILED DESC~I;PTION OF THE PREFER~ED EMBODI~NTS
First of all, it is to be.understood that the present invention is applicable to wire ropes in general irrespective of the wire rope core, strand core and fibre core. By way of example, the following description shows a wire rope with a wire rope core, more specifically, IWRC 6 x Fi(25) JIS Type 14.
Referring to Fig. 1, designated by reference number 1 is a core rope, by 2 six outer strands arranged around the outer periphery of core rope l, and by 3 a filler element which fills independently each one of the interstices a which are formed between core rope 1 and outer strands 2. Filler element 3 of a thermoplastic resin or the like is formed into a cord-like shape substantially of triangular cross-section in con~ormity with the interstice a, as shown in Fig. 2, and laid together with core rope 1 and outer strands 2 at the time of closing the rope to fill the respective interstices a independently of each other like outer strands 2. In this instance, iller elements 3 are pre-ferably formed slightly larger than the cross-section of the interstices a. By so doing, filler elements 3 are securely con-tacted with core rope 1 and outer strands 2 by the closing pressure, enhancing the efects o the iller elements all the more, namely, the effect of separating core rope 1 and outer strands 2 from each other and the effect of sealing the lubricant oil (not shown) which is impregnated between core rope 1 and outer strands 2.
The outer strands of the wire rope are arranged to ~ 163~79 1 have a percentage of voids in the range of 2,0 - 6.0%, The grounds for this definition of the value of the percentage of voids h are shown below, circumference of sum o~ arc AB
~ercentage pitch circle of wire rope - (= 6 ~) of voids h = (= 2~) x 100 (%) 2~y 10 ~

When a wire rope which has a percentage of voids greater than about 2% is bent on a sheave, it is possible to avoid con-tacts of the strands on the inner side (compression side) of the bend. This is the reason why the minimum value of the pQr-centage of voids h is set at 2.0%. On the other hand, if the percentage of voids h exceeds 6.0~, the core rope is exposed to an external view, lowering the commercial value of the wire rope. In addition, a percentage of voids greater than 6% in-variably requires reduction in the diameter of the outer strands, making it difficult to guarantee the standard breaking load.
Thus, the maximum value of the percentage of voids h is 6.0%.
Accordingly, in the present invention, the filler elements 3 are laid with a precondition that the percentage of voids h is 2.0 to 6,0%.
It is preferred to anchor a reinforcing core 4 of a 30 wire or hemp centrally in respective filler elements 3.

1 163&79 1 Reinforcing core 4 contributes to strengthen filler elements 3 and to prevent its cracking or peeling especially when in ser~ice as a running rope, while improving the breaking characteristics of the wsre rope as a whole. Further, it also has an effect of preventing the filler element from rupturing, falling or twisting during the clos-ing operation.
In addition to the shapes shown in Figs. 1 and 2, it is possible to form filler elements 3 in various other shapes as shown in Fig. 3. According to the present inventionj such is formed into a suitable shape which conforms to the interstice a.
The above-described filler-laid wire rope is fabricated by the method and apparatus as follows. Referring to Figs. 4 and 5, indicated by reference number S is a feeder for core rope 1, by 6 bobbins for the outer strands 2 and filler elements 3, by 7 a guide plate, by 8 a closing die, by 9 an oil feed tank, by 10 capstans and by 11 and take-up reel. Guide plate 7 is provided with a core rope passing hole 7a at the center thereof, filling passing holes 7b formed in positions radially outward of the core rope passing hole 7a, and outer strand passing holes 7c formed in positions radially outward of filler passing holes 7b. Filler passing holes 7b are preferably formed sub-stantially in the same shape as filler element 3 to guide the latter in a correct posture. Core rope 1 and filler elements 3 which are supplied from feeder S and bobbins 6 are passed through respective holes 7a and 7b of guide plate 7 and thereby held in predetermined positional relationship before being intertwisted by closing die 8. The filler-laid wire rope of Fig. 1 is thus produced and taken up on reel 11. Thus, the wire rope of the invention can be produced easily fundamentally by the conventional wire rope fabricating method and apparatus, ~ 163i79 t maintaining core rope 1, outer strands 2 and filler elements 3 in predeterminea positional relationship ~y guide plate 7.
With the wire rope of the invent;on~ it is possi~le to lessen considerably the contact pressure as caused between core rope 1 and the respective outer strands 2 by a dynamic load especially during service as a running rope, thereby reducing abrasion and fatigue of core rope 1 and outer strands

2 as well as the loss of wire rope breaking load by stranding and closing. Further, filler elements 3 seal in and prevent exudation of the lubricant oil which is impregnated into core rope 1 and outer strands 2. Consequently, the abrasive resist-ance and fatigue strength of the wire rope as a whole are im-proved while reducing the loss of wire rope breaking load by stranding and closing. F~rthermore, the entrapped lubricant oil lessens the necessity for relubrication when the wire rope is in service and has the effect of preventing internal corrosion over a long period of time.
In addition to the above-mentioned fundamental effects, filler element 3 has another advantage in that no possibility ~0 exists of impairing the flexibility of the wire rope as a whole since the filler element is laid independently ahd thus structur-ally separately in the respective interstice a. Besides, as mentioned hereinbefore, reinforcing core 4 protects the filler element against damage, i.e. rupturing or peeling, to ensure the àbove-mentioned effects of the filler elements for a re-Iatively long period of time.
Illustrated in Figs, 6-9 are second and third em-bodiments of the wire rope according to the present invention.
In the wire rope of Fig, 6, in addition to the filler elements

3 which are laid in the interstices a between core rope 1 and ~ 163~79 1 outer strands 2 in the same ~anner as in the foregoing embodiment, filler elements 3' o~ a shape ~itting to the outer strand gaps b (filler elements 3 and 3' are hereinafter referred to as "inner filler element'l and "outer filler element", respectively) are laid independently in the outer strand gaps b, In the wire rope construction of Fig. 8, inner and outer filler elements 3 and 3' which are formed into an integral body as shown par-ticularly in Fig. 9 are laid in each interstice a and an outwardly contiguous outer strand gap b, treating the interstice a and the contiguous gap b as an independent unit.
The wire ropes shown in Figs~ 6, and 8 lessens not only the contact pressure between core rope 1 and outer strands 2 but also the contact pressure between the individual outer strands 2, improving the wire rope as a whole in abrasive resistance, fatigue stre~gth and loss of wire rope breaking load by stranding and closing. Particularly, these effects are manifested more pronouncedly in the wire rope construction of Fig. 8 in which the outer strands 2 are completely separated by ' the bridge portions of the inner and outer filler elements 3 and 3'. These wire ropes also give excellent results in the effect of entrapping the lubricant oil.
The wir,e rope construction of Fig, 6 provides sub-stantially the same effect as in the embodiment of Fig. 8 if inner and outer filler elements 3 and 3' are arranged to contact with each other in the radial direction. In the wire rope constructions of Fig. 6 and 8, the effect of entrapping the lubricant oil i's augmented by contacting the adjacent outer ' filler elements 3' with each other through circumferentially extending film portions in such a manner that the outer peri-pheries of outer strands 2 are covered by,the contacting film ~ ~63~79 1 portions. On the other hand, although the reinforcing cores 4are anchored in both the inner and outer filler elements in these wire rope constructions, they may be embedded basically only in inner filler elements 3 except for a special application or a case where increased effects of the filler elements are desired.
The foregoing wire ropes are also fabricated by laying the filler elements concurrently with the outer strands at the time of closing in the same manner as in the wire rope construction of Fig. 1. Needless to say, the resulting wire ropes also have the effects unique to the present invention, namely, retaining flexibility and preventing cracking or peeling of the filler elements, similarly to the wire rope construction of Fig. 1.
In the above-described concurrent filler-laying method which has been employed for the fabrication of the wire rope of the invention, the filler elements are laid in simultaneously with the closing operation so that there is no need for providing a separate filler-laying stage in the fabrication process, thus ensuring high production efficiency of the rope. The method also has advantages over the conventional coating method since it does not require the preheating treatment of the rope prior to impreg-nation of the filler material nor equipment like an extruder.
The low equipment cost, coupled with the high productivity of the rope, permits realization of a material cost reduction of the wire rope. ~n view of these points, the simultaneous filler-laying method is considered to be the most advantageous and suit-able method for the fabrication of the wire rope of the present invention and thus to be the sole method which is conceivable for actual application. However, any other method may be employed as long as the filler elements can be laid in the same manner.

~ 163&79 The following experiments more particularly illustrate the fatigue strength and other properties of the wire rope ac-cording to the present invention.
(Experiment 1) The following wire rope specimens of IWRC 6 x Fi(25) 16 mm JIS Type 14 were subjected to a repeated bending test.
(i) A black wire rope;
(ii) A wire rope construction of Fig. 1 according to the invention; and (iii) A conventional wire rope having interstices and gaps completely and integrally impregnated and filled with a thermoplastic resin.
In the test, a pair of testing sheaves were positioned between a drive sheave and a tension sheave and specimens (i) to ~iii) were passed in S-shape through the testing sheaves, fixing their opposite ends to the drive and tension sheaves through auxiliary ropes. A horizontal tensile load was applied to the tension sheave during repeated bending tests under the following conditions .
Rope diameter d (mm): 16 Testing sheave pitch diameter D (mm): 256 D/d ratio: 16 Testing load (kg): 1190 Nominal breaking load of test wire rope ~kg): 11900 Safety factor: 10 Sheave arrangement: S-shape The test results are shown in Table 1.

~ 163~79 1 Ta~le 1 .. _ Specimens Number of repeated bendings (times) _ Initial wire 10% wire breaking breakina (terminal point of test) _ (i) 8500 17000 (ii) 12500 26500 (iii) 13000 27500 (Experiment 2) The following wire rope specimens of n~Rc 6 x Fi(29) 44 mm were tested for flexibility, increase in diameter and loss of wire rope breaking load by stranding and closing.
The test results are shown in Table 2.
~i) A black wire rope;
(ii) A wire rope construction of Fig. 1 according to the invention; and ~iii) A conventional wire rope having interstices and gaps completely and integrally impregnated and filled with a thermoplastic resin.
Table 2 , Flexi- Ro e diameter Loss of jspecimens bility P Increment breaking load , (i) 100 44.80 O 18.1~23.1 45.46~45.58 +1.47_+1.74 ~ii) 95flOO 46.26 46.38 +3.26~~3.5 14.1~18.1 ~iii) 70f75 14.5~19.0 The flexibility is expressed by an index number based on 100% of the black rope (specimen (i)), and the loss of wire breaking load by stranding and closing is expressed by:

~ 1~3~7g 1 ~oss of breaking load (%) = (l- actual ~reaking lo-ad of wire rope 0 aggregate breaking load of ) x l0 - individual wires The results of Experiments l and 2 show that the wire rope of the present invention is almost comparable to the com-pletely impregnated wire rope with regard to the repeated bending strength in spite of the fact that the tested specimen was of the construction of Fig. l with the filler elements laid only in the inner interstices, and excels the latter in the flexibility and loss of wire rope breaking load as well as the increment in diameter.
It will be appreciated from the foregoing description that the wire rope of the present invention retains the improved properties of the impregnated wire rope in abrasive resistance, fatigue strength and loss of wire rope breaking load by stranding and closing, without impairing the flexibility of the wire rope, while preventing cracking and peeling of the filler material, and thus has an extremely high practical use character-istic.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings.
It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A wire rope comprising:
a core rope;
a plurality of outer strands laid on the circumference of said core rope so as to form a plurality of interstices between said core rope and said respective outer strands; and a flexible filler element formed as an integral body with an embedded reinforcing core independently disposed in each of said interstices formed between said core rope and said respective outer strands.

2. A wire rope comprising:
a core rope;
a plurality of outer strands laid on the circumference of said core rope having gaps formed therebetween and forming a plurality of interstices between said core rope and said respective outer strands;
a flexible filler element formed as an integral body independently disposed in each of said interstices formed between said core rope and said outer strands and in each of said gaps between the individual outer strands; and a reinforcing core embedded in at least said filler element disposed in said interstices.

3. A wire rope comprising:
a core rope;
a plurality of outer strands laid on the circumference of said core rope having radially outwardly extending contiguous gaps formed therebetween and forming a plurality of interstices between said core rope and said respective outer strands; and

Claim 3 continued ...

a flexible filler element formed as an integral body disposed in the interstices formed between said core rope and the respective outer strands and the radially outwardly extending contiguous gaps between the individual outer strands such that one interstice and a radially outwardly extending con-tigous gap comprise a single independent unity, wherein said filler element further comprises a reinforcing core embedded therein at least in a portion located within said interstices.