US3092956A - 7-strand wire rope - Google Patents

Description

June 11, 1963 A. M. NAYSMITH 'I-STRAND WIRE ROPE 2 Sheets-Sheet l Filed sept. 8, 1960 June 11, 1963 A. M. NAYsMlTH 3,092,956

v-sTRAND WIRE ROPE Filed sept. 8. 1960 2 sheets-sheet 2 W w m, w ,l/ 7 a United States Patent O 3,092,956 7-STRAND WIRE ROPE Archibald M. Naysmith, Kenosha, Wis., assignor to Macwhyte Company, Kenosha, Wis., a corporation of Wisconsin Filed Sept. 8, 1960, Ser. No. 54,748 6 Claims. (Cl. 57-145) This invention relates in general to wire ropes and in particular to a wire rope having excellent flexibility characteristics combined with good resistance to drum crushing, and excellent abrasion resistance.

Probably the most widely used wire rope today is a six-strand rope. This particular construction has good properties for a wide variety of uses, lbut in many respects it represents only a compromise of a good many qualities. For example, experience has shown that greater liexibility can be obtained by increasing the number of strands. At the same time, the fatigue resistance is increased by increasing the number of strands because the diameter of each strand is decreased. Consequently, each strand is less subject to -fatigue failure as it passes around a pulley or other direction reversing element.

Although fatigue resistance and exibility properties are increased with an increase -in strands, fthe resistance of the rope to `drum crushing decreases. This is due to the fact that, for a given size rope, with an increase in the number of strands, the core diameter increases because the diameters of the individual strands decreases. As a result, when heavy loads are imposed on the wire rope as it is wrapped around the drum, the tendency for the rope to collapse is considerably increased. In addition, the increase in the number of strands also decreases the abrasion resistance of the wire rope.

Because of the decrease in drum crushing resistance and abrasion resistance, it has heretofore not been thought possible to obtain the desirable qualities of a six-strand rope by increasing the number of strands.

Accordingly, a primary object of this invention is to provide a wire rope of more than six strands having good resistance to drum crushing and excellent abrasion resistance while retaining all of the desirable advantages of the conventional six-strand wire rope.

Yet another object is to provide a wire rope of more than six strands which will permit coarser abrasion resistant strand constructions to be utilized than are presently employed in six-strand ropes without sacrificing tiexibility and fatigue resistance characteristics.

Yet another object is to provide a seven-strand wire rope which has increased exibility and traction properties as contrasted to a conventional six-strand wire rope.

Yet another object is to provide an all-purpose sevenstrand wire rope suitable for use in nearly all applications in which a six-strand wire rope has been found desirable, and many more.

These and other objects and advantages of the invention will become apparent upon reading the following description of the invention.

'Ihe invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:

FIGURE 1 is an elevation of the wire rope of this invention;

FIGURE 2 is a section through a wire rope of this invention illustrating a basic 7 x 19 construction, in this instance a twenty-one-tiller-wire strand construction; and

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FIGURE 3 is a View similar to FIGURE 2 illustrating another basic 7 x 19 construction, in this instance a twentj-iive-iller-wire strand construction.

Like reference numerals will be used to refer to like parts throughout the following description of the invention.

The wire rope of this invention is indicated generally at 10 in FIGURE l. The rope is composed of seven strands. Each strand is identied by the reference numeral 1 through 7, respectively, across the top of the strand. The reference numeral 8 indicates generally a core which in this instance is a fibrous material as will be discussed in detail hereinafter. A standard right regular lay has been illustrated. It will be understood, however, that either a right or left regular lay -be used, or even a right or left lang lay. In addition, any one of the four above-described lays may be utilized `in combination with either a wire rope or fiber core. In other words, the specific structure of the invention is not limited to any particular lay, grade, core or classification of rope.

The wire rope of FIGURE 1 is illustrated in more detail in FIGURE 2. -In this iigure, each of the individual, seven strands is indicated by its corresponding reference numeral used in the `description of FIGURE 1. Each of the strands is illustrated in more detail but since Vthe construction of the individual strands is identical a description of one will suice for all.

Each strand consists essentially of au outer ring of ten wires numbered consecutively from 11 through 20. Tibis outer ring surrounds an inner ring of iive wires numbered consecutively from 21 through 25. This inner ring in turn surrounds a core wire 31. A plurality, in this instance live, ller wires numbered consecutively from 26 through 34), are :interposed between the inner and outer rings to fill in the interstices between the inner and outer rings.

The core `8 may be of any conventional librous material. In this instance, the rope has been so formed that the ber has penetrated into the crevices between adjacent wires, as indicated, for example, at 32.

In FIGURE 3, the basic seven-strand wire rope is again illustrated, but in this instance, it is shown in a 7 x 25 Eller wire construction, basically a 7 X 19 classification as is well known in the art. Each strand in this instance consists of an outer ring of twelve wires numbered consecutively from 4t) through 51, and an inner ring numbered consecutively from 52 through 57. The inner ring in tur-n surrounds a center `'wire 58. As inthe embodiment of FIGURE 2, a plurality, in this instance six, filler wires 59 through 64, respectively, are located yin the interstices between the inner and outer rings of wires.

In this construction the convention liber core 8 of FIGURE 2 has been replaced by an independent wire rope core indicated generally at 9. The core consists essentially of six groupings of seven-wire strands indicated generally at 7 0 through 7 5 which surround an inner grouping 76. In this instance, the wires of each group of wires is of uniform diameter, but it will be understood that it is possible within the scope `of the invention to utilize core wires having lindividual wires of diering diameters. For ease of illustration and description basic 7 x 19 constructions have been shown rather than 7 x 37 constructions, which likewise are well known in the art.

The following table illustrates the weights and breaking strengths of two qualities or grades of the seven-strand rope of this invention for various rope diameters. The

values given yare illustrative only, and are not intended to be limitative with respect to strand construction, classication, grade, quality, weights, or breaking strengths. It will be apparent at once upon a review Iof the tabular data that the breaking strengths of the wire rope of this invention compares very favorably with the conventional six-strand wire rope which is so widely used commercially today.

7-sTRAND WIRE ROPEXX-VBREAKING STRENGTHS AND EIGHTS [19 Wire classifications] Rope A 1 Rope B 2 Approx. weight, lbs/ft. Rope dia., inches Breaking strength in tons of 2000 lbs.

11.0.3 IWRC 4 F.G. IWRC IWRO l, 2 Two grades of wire rope differing from one another primarily in the method of heat treating the wires. All wires are made from a 1074 steel containing approximately .70-.80 carbon and .5U-.70 manganese as the principal alloying elements.

5 Fiber core.

4 Independent wire rope core.

Norm-Average modulus value in F.C.=12,000,000 p.s.i. Average modulus value, IWRC =13,000,000 p.s.i. Average metallic area, F.C 0. 390xnom. dia.squared. Average metallic area, IWRC =0. 480xnom. dia. squared.

Actual eld tests have also borne out the fact that the seven-strand wire rope -of this construction is often as good, and may be better in resistance to drum crushing than the conventional six-strand wire rope. This -is exactly contrary to lwhat Would normally be expected, because `as the number of strands is increased it has heretofore been thought that the resistance to drum crushing -is decreased. This, of course, is due to the fact that the increased number of strands for any given diameter results in a progressively langer core being formed. The larger the core, the more susceptible the wire rope is to drurn crushing. The actual eld tests were conducted in connection with lines used on scraper wagons.

These improved results were also achieved with increased flexibility over the conventional six-strand rope.

The service applications of seven-smand wire ropes are many and varied and include:

Car puller and car spotter ropes. Logging straw lines.

(10) Winch lines.

(11) Boom hoist lines.

(12) Ladle crane ropes.

(13) Shop hoists and cranes. (14) Blast furnace skip hoists.

In addition to the unusual feature of at least equal drum crushing characteristics as contrasted to a conventional six-strand wire rope, the seven-strand wire rope `of this invention has at least as good labrasive resistance, more fatigue resistance, 4and better traction properties than the conventional six-strand Wire rope. Y

Although the invention has been illustrated in conjunction with Itwo types of nineteen Wire strand classification and ltwo different core constructions, it will be at once apparent to one skilled in the art that the principles of the invention are readily -applicable to `other types `and classiication of strand construction. Accordingly, the illustratedembodiments are therefore to be taken as illustrative only, and the scope of the invention should only be limited by the scope of the following appended claims.

I claim: 1. An all purpose, substantially non-elastic, high strength wire rope having excellent flexibility and drum crushing characteristics,

said wire rope having a core extending the length of the rope and seven strands extending the length of the core, said strands being Ilaid around the core in snug frictional engagement therewith, said wire rope having a constant external diameter along its length, each stnand being composed of a plural-ity of wi-res laid about a wire core. 2. The all purpose high strength wire rope of claim 1 further characterized in that the diameter of the wire rope lies in the range of 3%; inch to 11A inches inclusive. 3. The yall purpose high strength Wire rope of claim 1 further characterized in that the wire rope is off a basic 7 x 19 construction. Y

4. The Aall purpose high `strength wire rope of claim 1 further characterized in that the wire rope is of a basic 7 X 37 construction. I

5. The allV purpose high strength wire rope of claim 1 further characterized in that the rope has an independent wire rope core.

6. The a-ll purpose high strength wire rope of claim 5 further characterized in that the lay is a type selected from the :group consisting bf right regular, left regular, right lang, and `left lang.

References Cited in the le of this patent UNITED STATES PATENTS 861,230 Allan July 23, 1907 1,183,487 Parker May 16, 1916 1,427,471 Howe Aug. 29, 1922 1,786,936 Craig Dec. 30, 1930 1,916,135 Gates June 27, 1933 2,387,829 Burnham etal Oct. 30, 1945 2,480,005 Ewell Aug. 23, 1949

Claims (1)

1. AN ALL PURPOSE, SUBSTANTIALLY NON-ELASTIC, HIGH STRENGTH WIRE ROPE HAVING EXCELLENT FLEXIBILITY AND DRUM CRUSHING CHARACTERISTICS, SAID WIRE ROPE HAVING A CORE EXTENDING THE LENGTH OF THE ROPE AND SEVEN STRANDS EXTENDING THE LENGTH OF THE CORE, SAID STRANDS BEING LAID AROUND THE CORE IN SNUG FRICTIONAL ENGAGEMENT THEREWITH, SAID WIRE ROPE HAVING A CONSTANT EXTERNAL DIAMETER ALONG ITS LENGTH, EACH STRAND BEING COMPOSED OF A PLURALITY OF WIRES LAID ABOUT A WIRE CORE.

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