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WO2025058978A1 - Braided cover for roundsling having twist in core yarns and related method - Google Patents

Braided cover for roundsling having twist in core yarns and related method Download PDF

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Publication number
WO2025058978A1
WO2025058978A1 PCT/US2024/045802 US2024045802W WO2025058978A1 WO 2025058978 A1 WO2025058978 A1 WO 2025058978A1 US 2024045802 W US2024045802 W US 2024045802W WO 2025058978 A1 WO2025058978 A1 WO 2025058978A1
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WO
WIPO (PCT)
Prior art keywords
yarns
cover
roundsling
core
yams
Prior art date
Application number
PCT/US2024/045802
Other languages
French (fr)
Inventor
Gregory D'elia
Forrest T. BLANKENSHIP
Original Assignee
Slingmax, Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Slingmax, Llc filed Critical Slingmax, Llc
Publication of WO2025058978A1 publication Critical patent/WO2025058978A1/en

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Classifications

    • DTEXTILES; PAPER
    • D07ROPES; CABLES OTHER THAN ELECTRIC
    • D07BROPES OR CABLES IN GENERAL
    • D07B7/00Details of, or auxiliary devices incorporated in, rope- or cable-making machines; Auxiliary apparatus associated with such machines
    • D07B7/16Auxiliary apparatus
    • D07B7/165Auxiliary apparatus for making slings
    • DTEXTILES; PAPER
    • D04BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04CBRAIDING OR MANUFACTURE OF LACE, INCLUDING BOBBIN-NET OR CARBONISED LACE; BRAIDING MACHINES; BRAID; LACE
    • D04C1/00Braid or lace, e.g. pillow-lace; Processes for the manufacture thereof
    • D04C1/06Braid or lace serving particular purposes
    • D04C1/12Cords, lines, or tows
    • DTEXTILES; PAPER
    • D07ROPES; CABLES OTHER THAN ELECTRIC
    • D07BROPES OR CABLES IN GENERAL
    • D07B1/00Constructional features of ropes or cables
    • D07B1/02Ropes built-up from fibrous or filamentary material, e.g. of vegetable origin, of animal origin, regenerated cellulose, plastics
    • DTEXTILES; PAPER
    • D07ROPES; CABLES OTHER THAN ELECTRIC
    • D07BROPES OR CABLES IN GENERAL
    • D07B2201/00Ropes or cables
    • D07B2201/20Rope or cable components
    • D07B2201/2083Jackets or coverings
    • D07B2201/209Jackets or coverings comprising braided structures
    • DTEXTILES; PAPER
    • D07ROPES; CABLES OTHER THAN ELECTRIC
    • D07BROPES OR CABLES IN GENERAL
    • D07B2205/00Rope or cable materials
    • D07B2205/20Organic high polymers
    • D07B2205/201Polyolefins
    • D07B2205/2014High performance polyolefins, e.g. Dyneema or Spectra

Definitions

  • Synthetic fiber roundslings have been used in industry for a number of years for lifting loads in industrial applications such as manufacturing, construction, cargo handling, and many other applications where low weight, flexibility, versatility, strength and corrosion resistance are desired. Constructing roundslings from synthetic fibers provides advantages compared to traditional steel wire rope rigging including significantly lower weight, enhanced flexibility, and faster rigging time.
  • Synthetic fiber roundslings include a woven protective cover and a loadbearing core constructed of individual yarns.
  • the load-bearing core yarns generally carry the force applied to the sling, while the cover provides structure and protection for the roundsling.
  • the woven protective cover of prior art roundslings is relatively rigid for a fabric such that the tubular cover does not readily flex to accommodate a variable number of core strands leaving slack in the woven protective cover and empty space between the woven protective cover and the core strands.
  • the woven protective cover may require a wrap along its length to reduce the diameter of the prior art roundsling for ready connection to rigging hardware, which has a connection hook or joint accommodating only a limited size or diameter.
  • the protective roundsling covers include synthetic fibers that are constructed into a tubular form using manufacturing methods including, but not limited to, weaving, braiding, or knitting.
  • the cover provides structure to the roundsling by constraining the load bearing core yarns in the correct configuration and geometry.
  • the cover also protects the core yarns from damage from a number of factors including physical (e.g, cutting, snagging, and abrasion), ultraviolet degradation (from sunlight or artificial sources), chemical attack and other external irritants.
  • the load-bearing core yarns are typically constructed from synthetic fibers or strands that are formed into a bundle using manufacturing methods including, but not limited to, twisting, braiding, or stranding.
  • Synthetic round slings may be made by winding the core yarns in an endless loop into the tubular protective cover. The winding is typically performed using a powered drive roller on one end and an unpowered idler roller or fixed roller on the other. The rollers are set a certain distance apart to produce the desired length of the roundsling. The desired capacity of the sling is achieved by winding multiple revolutions of core yarns into the cover.
  • the total capacity of the sling is determined by multiplying the load-bearing capacity of one core yarn by how many total yams are included in the sling or roundsling. This value is then divided by a design factor (sometimes referred to as safety factor) to arrive at a rated working load.
  • a design factor sometimes referred to as safety factor
  • twisting or stranding fibers together when manufacturing fiber ropes results in an increased strength efficiency of the rope.
  • the twisting or stranding process equalizes the tensions between the component fibers, allowing greater loadsharing when the finished rope or sling is placed under tension because there is a reduced tendency to have tighter and looser fibers in the rope under loading.
  • the nature of building a synthetic fiber roundsling or sling precludes the possibility of twisting the load-bearing core yarns together, thereby resulting in the potentially unbalanced loading of the individual core yams during use.
  • the fibers or core yarns in a prior art roundsling are not twisted or stranded because the process requires each of the component strength members to be loaded onto separate reels or bobbins and placed into rotating machinery designed to form a rope or sling, which is not possible with the roundsling manufacturing process with the drive and fixed rollers.
  • the component strength member is fed directly into the cover, precluding this twisting or stranding.
  • a preferred embodiment of the invention is directed to a roundsling for lifting heavy loads, wherein the roundsling includes a plurality of core yarns and a braided cover with a plurality of cover yarns.
  • the plurality of cover yarns includes a first plurality of yams and a second plurality of yams.
  • the plurality of core yarns is configured to bear the heavy load of the roundsling during use.
  • the plurality of core yams are wrapped, stranded or twisted in a circular, spiral cylindrical or helix configuration and is constructed of a polymeric material.
  • the first plurality of yams has a first linear density and the second plurality of yarns has a second linear density. The first linear density is greater than the second linear density.
  • the plurality of core yarns is oriented in a helical pattern within the braided cover.
  • the preferred invention is comprised a synthetic roundsling including a helically laid load-bearing core yarn within a braided fiber protective cover.
  • the roundsling is constructed such that the load-bearing core yarns are twisted or stranded as the core yarns are fed through the braided protective cover during manufacture or assembly.
  • the core yarns are, therefore, positioned within the protective cover with a helical twist or pattern in an assembled configuration.
  • the roundsling which is manufactured in this way with the helically arranged core yarns, provides added strength efficiency compared to a roundsling manufactured using traditional methods, wherein the core yarns of the traditional or prior art roundsling are not twisted or are arranged generally linear or parallel to each other in the core of the roundsling within the woven protective cover.
  • the cover includes a plurality of yams, including a first plurality of yarns and a second plurality of yarns.
  • the first plurality of yarns has a first linear density and the second plurality of yarns has a second linear density.
  • the first linear density is greater than the second linear density.
  • the core yarns are preferably twisted or stranded as the core yams are drawn through the preferred protective cover having the braided first and second plurality of yarns, wherein the first yarns have a greater linear density than a second linear density of the second plurality of yarns.
  • the first plurality of yarns of the protective cover are proud of the second plurality of yams.
  • a braid is defined by the number of carriers in the braiding machine used to make up the structure of the braid. Each carrier is loaded with a bobbin of fiber or yarn and the carriers travel in a pre-determined path to form the braided member.
  • Common braiding machines in the cordage industry include models with twelve, sixteen, twenty- four, thirty-two, forty-eight and ninety-six carriers (12, 16, 24, 32, 48 and 96), although the machines are not so limited and may include more or less carriers depending on designer and user preferences and application requirements. Braiding machines with these other numbers of carriers may be used to construct a braided structure.
  • Each carrier may hold one or more untwisted fibers, or one or more twisted yarns made up of fibers.
  • half of the carriers hold yams that are twisted in the “S” direction, then are braided in the “Z” direction, and the other half hold yarns that are twisted in the “Z” direction then are braided in the “S” direction.
  • the thicker or first yarns have a linear density of approximately sixteen to sixty thousand denier (16,000 - 60,000 den) and the smaller or second yarns have a linear density of approximately eight to thirty thousand denier (8,000 - 30,000 den).
  • the larger yarns may comprise anywhere from one strand to half of the total strands in the braided cover. In the preferred embodiments, however, four to twenty -five percent (4-25%) of the total strands in the braided cover are preferably comprised of the larger yarns, while seventy -five to ninety-six percent (75-96%) of the total strands in the braided cover are comprised of the smaller yarns. All of the larger strands are preferably braided in the same direction, such as the S-direction or the Z-direction, so that the induced twisting force on the core yams during assembly urges the core yams in the same direction.
  • the larger yams of the protective cover may be nearly any percent larger than the rest of the yarns in the braid of the protective cover, however, in the preferred embodiment, the larger yarns are approximately double the size of the smaller yams but are not so limited.
  • a method of constructing a roundsling having a braided cover and a plurality of core yarns on a synthetic sling manufacturing apparatus includes securing the braided cover on the synthetic sling manufacturing apparatus.
  • the braided cover is constructed of a first plurality of cover yarns oriented only in an S-direction and a second plurality of cover yarns oriented in the S-direction and a Z-direction with the first plurality of yarns being proud of the second plurality of yarns in the assembled configuration.
  • the method also includes introducing a first core yarn of the plurality of core yarns into the braided cover, running the plurality of core yarns through the braided cover such that the plurality of core yarns follow a pattern of the first plurality of yarns to orient the plurality of core yarns in a helical pattern within the braided cover and connecting opposing ends of the braided cover to enclose the plurality of core yams within the braided cover.
  • FIG. 1 illustrates side elevational views of two prior art individual core strands having a left-lay 5 (z.e., an “S” twist) and a right-lay 6 (z.t?., a “Z” twist), respectively;
  • a left-lay 5 z.e., an “S” twist
  • a right-lay 6 z.t?., a “Z” twist
  • Fig. 2 illustrates a side elevational view of a roundsling having a braided cover in accordance with a first preferred embodiment of the present invention
  • 2A illustrates a cross-sectional view of a portion of the braided cover of Fig.
  • FIG. 3 illustrates a side elevational view of a roundsling having a braided cover in accordance with a second preferred embodiment of the present invention
  • FIG. 4A illustrates a side elevational view of a roundsling having a braided cover in accordance with a third preferred embodiment of the present invention
  • Fig. 4B illustrates a side elevational view of a roundsling having a braided cover in accordance with a fourth preferred embodiment of the present invention
  • Fig. 4C illustrates a side elevational view of a roundsling having a braided cover in accordance with a fifth preferred embodiment of the present invention
  • Fig. 4D illustrates a side elevational view of a roundsling having a braided cover in accordance with a sixth preferred embodiment of the present invention
  • Fig. 4E illustrates a side elevational view of a roundsling having a braided cover in accordance with a seventh preferred embodiment of the present invention
  • Fig. 5 illustrates a top perspective view of a partially constructed roundsling positioned in a synthetic sling manufacturing machine, wherein a plurality of core yarns are fed into one of the preferred braided covers of Figs. 2-4E to define one of the preferred roundslings.
  • preferred embodiments of the present invention are directed to an improvement compared to synthetic slings having opposing lays, such as the synthetic sling described in U.S. Patent No. 8,322,765 (“‘765 patent”) or a rifled cover technology that involves a helical twisting induced in the core yarns by the woven cover.
  • the method in which the twisting of the synthetic sling is achieved in the ‘765 patent is a different mechanism compared to how core yams 16 are twisted within the braided cover 10 in the preferred embodiments of the present invention.
  • the twisting in the synthetic sling is induced by warp yams on the inner layer of the woven cover having a opposite twist as compared to the twisted core yarns being run into the tubular cover.
  • the present invention is directed to a roundsling, generally designated 18, for lifting heavy loads.
  • the roundsling 18 includes a plurality of core yams 16 configured to bear the heavy load during use.
  • the core yarns 16 are constructed of a polymeric material.
  • the core yams 16 of Fig. 2A are shown as a monolithic structure for convenience and clarity but are preferably comprised of bundles or the plurality of core yarns 16 that are twisted in a helical pattern, as is described herein.
  • the roundsling 18 also includes a braided cover 10 constructed of a plurality of cover yarns, including a first plurality of yarns 12 and a second plurality of yarns 14.
  • the first plurality of yarns 12 and the second plurality of yams 14 are shown in Fig. 2A as individual monolithic yams, but are not so limited and each of the individual yarns 12, 14 may be comprised of a bundle of filaments or strands that comprise the individual members of the first and second plurality of yarns 12, 14.
  • the braided cover 10 has a tubular construction such that the core yarns 16 may be contained therein in an assembled or working configuration.
  • the first plurality of yams 12 has a first linear density and the second plurality of yams 14 has a second linear density.
  • the first linear density is greater than the second linear density. In the preferred embodiment, the first linear density is approximately two to six times (2-6X) greater than the second linear density.
  • the plurality of core yams 16 is oriented in a helical pattern within the braided cover 10 in an assembled configuration.
  • the individual yams or bundles of the first plurality of yams 12 may have a first diameter DI and the individual yarns or bundles of the second plurality of yarns 14 may have a second diameter D2, wherein the first diameter DI is greater than the second diameter D2.
  • the first diameter DI may be approximately fifty hundredths of an inch to one hundred hundredth of an inch (0.050 - 0.100”) or one and twenty-seven hundredths millimeters to two and fifty-four hundredth millimeters (1.27 - 2.54 mm) and the second diameter D2 may be approximately ninety thousands inches to one hundred seventh-five thousands inches (0.90 - 0.175”) or two and twenty-nine hundredths to four and forty- five hundredths millimeters (2.29 - 4.45 mm).
  • the first and second diameters DI, D2 are not limited to these described ranges, but these size ranges are preferred for the braided cover 10 of the preferred embodiments but may be otherwise designed and configured depending on designer preferences, specific applications of the roundsling 18 or other design factors.
  • the core yarns 16 are constructed of a polymeric material.
  • the polymeric material of the core yarns 16 may be comprised of ultra-high molecular weight polyethylene (UHMPE or HMPE, such as Dyneema® or Spectra®), aromatic polyesters (e g., liquid crystal polymers (LCP) such as Vectran®), para-aramid (such as Kevlar®, Twaron®, or Technora®), meta-aramid (such as Nomex®), polyester, nylon, polypropylene or other polymeric or synthetic materials.
  • UHMPE or HMPE such as Dyneema® or Spectra®
  • aromatic polyesters e g., liquid crystal polymers (LCP) such as Vectran®
  • para-aramid such as Kevlar®, Twaron®, or Technora®
  • meta-aramid such as Nomex®
  • polyester nylon, polypropylene or other polymeric or synthetic materials.
  • the core yarns 16 are not limited to the specific polymeric materials described herein and may be comprised of nearly any material that is able to take on the general size and shape of the core yams 16, withstand the normal operating conditions of the core yarns 16 and perform the preferred functions of the core yams 16, as described herein.
  • the plurality of cover yarns 12, 14 are similarly, preferably constructed of a polymeric material, wherein the polymeric material of the cover yarns 12, 14 is preferably comprised of ultra-high molecular weight polyethylene, aromatic polyester, para-aramid, meta-aramid, polyester, nylon, polypropylene or other polymeric or synthetic materials.
  • the plurality of cover yarns are not limited to the specific polymeric materials described herein and may be comprised of nearly any material that is able to take on the general size and shape of the plurality of cover yams 12, 14, withstand the normal operating conditions of the plurality of cover yarns 12, 14 and perform the preferred functions of the plurality of cover yarns 12, 14, as described herein.
  • the preferred invention can induce twist in other types of core yarns 16, for example, ones that are made with a braiding process or nearly any other variety of core yarns 16, regardless of their direction of twist.
  • a woven roundsling cover such as the cover of the ‘765 patent, is generally fixed into the width that is established when the jacket is manufactured.
  • the braided tube or cover 10 of the preferred embodiment can expand and contract depending on the size of the core yarn 16 or the number of core yarns 16 that is inside the cover 10. This means that in the preferred invention, the braided cover 10 may to conform to the size or volume of the plurality of core yarns 16 during use, further reducing the final diameter of the roundsling 18 and making it easier to fit the roundsling 18 into smaller lifting points, thereby providing an advantage over the roundsling of the ‘765 patent.
  • the braided cover 10 of the preferred embodiments provides flexibility to confirm to different sizes and volumes of the plurality of core yams 16, while the woven cover of the roundsling of the ‘765 patent is more rigid, resulting in assemblies where empty space may be present between the internal surface of the cover and the core yarns.
  • a second preferred embodiment of the roundsling 18' includes similar features compared to the features of the first preferred roundsling 18.
  • the same reference numerals are utilized to identify the same features of the second preferred embodiment with a prime symbol (') utilized to distinguish the features of the second preferred roundsling 18' from the features of the first preferred roundsling 18.
  • the first plurality or larger yarns 12, 12' of the cover 10, 10' may comprise anywhere from one strand to half of the total strands in the braided cover 10, 10'.
  • the first plurality or larger yarns 12, 12' may comprise four to twenty-five percent (4-25%) of the total strands in the braided cover 10, 10', while the second plurality or smaller yams 14, 14' may comprise seventy-five to ninety-six percent (75-96%) of the total strands in the braided cover 10, 10'.
  • the first plurality or larger strands or yams 12, 12' are preferably braided in the same direction, such as the S-direction or the Z-direction, so that the induced twisting force on the core yams 16 during assembly urges the core yarns 16 to twist in the same direction.
  • the first plurality or larger strands or yarns 12, 12' is oriented only in the S-direction in the braided cover 10, 10' and the second plurality of yarns 14, 14' is oriented in both the S-direction and the Z- direction.
  • first, second, third, fourth, fifth, sixth and seventh preferred embodiments of the roundsling 18, 18', 18", 18'", 18"", 18'"", 18"" may be constructed having the larger or first plurality of strands or yarns 12, 12', 12", 12'", 12"", 12"'", 12"”” in differing percentages compared to the smaller or second plurality of strands or yarns 14, 14', 14", 14'", 14'"', 14'"", 14""” in the total strands of the braided cover 10, 10', 10", 10'", 10"", 10'"", 10"""".
  • the first preferred embodiment of the cover 10 has the least percentage of larger strands 12 in the braid while the seventh preferred cover 10""" has the most or highest percentage of larger strands 12'""', with the third, fourth, fifth and sixth preferred covers 10", 10'", 10"", 10'"" having increasing percentages of larger strands 12", 12'", 12"", 12'"" between the first and seventh preferred covers 10, 10""".
  • cover 10, 10", 10'", 10"", 10"'", 10'"' illustrate that the cover 10, 10", 10'", 10"", 10'"", 10""” may be constructed having various percentages of larger and smaller strands 12, 12", 12'", 12"", 12'"", 12""", 14, 14", 14'", 14"", 14'"", 14""” with the preferred construction and assembly method of the invention described herein.
  • the covers 10, 10', 10", 10'", 10'"', 10'"", 10"" of the preferred embodiments also define the braid angles A, A', A", A'", A"", A'"", A”"” measured relative to the braid axis 10a, 10a', 10a", 10a'", 10a"", 10a'"", 10a"""".
  • the sling manufacturing machine 30 includes a drive roller 38 that draws the individual strands or yams or multiple strands or yarns of the plurality of core yarns 16 into the cover 10, 10", 10'", 10"", 10""', 10""".
  • the plurality of core yarns 16 are comprised of continuous yarns or strands that wrap around itself within the cover 10, 10', 10", 10"', 10"", 10'"", 10""" a predetermined number of times depending on the size or rating of the roundsling 18, 18', 18", 18'", 18'"', 18'"", 18""” and the number of individual strands or yams driven by the drive roller 38.
  • the roundsling 18, 18', 18", 18'", 18"", 18"'", 18'""' is manufactured by selecting the appropriate cover 10, 10', 10", 10'", 10"", 10'"", 10""", cutting the cover 10, 10', 10", 10'", 10”", 10'"", 10""" and connecting a cut first end 10b of the cover 10, 10', 10", 10'", 10"", 10'"", 10""" to a cross-bar 83 of the sling manufacturing machine 30.
  • the plurality of core yams 16 are drawn through the inside of the cover 10, 10', 10", 10'", 10"", 10'"", 10""" and the proud larger strands 12, 12", 12'", 12"", 12'"", 12""" drive the core yarns 16 to twist within the cover 10, 10', 10", 10'", 10"", 10'"", 10""".
  • the thicker or larger strands 12, 12", 12'", 12"", 12"'", 12"” have a linear density of approximately sixteen to sixty thousand denier (16,000 - 60,000 den) and the smaller yams 14, 14", 14'", 14"", 14'"", 14""”, have a linear density of approximately eight to thirty thousand denier (8,000 - 30,000 den).
  • the roundsling 18, 18', 18", 18'", 18"", 18'"", 18"" with the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""" and plurality of core yarns 16 is constructed or assembled partially using the sling manufacturing machine 30.
  • the preferred roundsling 18, 18', 18", 18'", 18"", 18"'", 18"”” is assembled by securing a first end 10b of the tubular cover 10, 10', 10", 10'", 10"", 10'"", 10""" to the cross bar 83 of the sling manufacturing apparatus or the sling manufacturing machine 30.
  • a first core yarn 16 of the plurality of core yarns 16 is introduced into the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""" and the plurality of core yams 16 are run or pulled through the braided cover 10, 10', 10", 10'", 10"", 10'"”, 10"'"' such that the plurality of core yarns 16 follows a patterns of the first plurality of cover yarns 12, 12", 12'", 12"", 12'"", 12"””” to orient the plurality of core yarns 16 in a helical pattern within the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""".
  • the plurality of core yams 16 are preferably fed from spools over the drive roller 38, into the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""", around a follower roller (not shown), out of a second end 10c of the cover 10, 10', 10", 10'", 10"", 10'"", 10””” and back over the drive roller 38.
  • the sling manufacturing machine 30 drives the plurality of core yarns 16 a predetermined number of revolutions to position the predetermined number of the plurality of core yarns 16 into the cover 10, 10', 10", 10'", 10"", 10'””, 10”””.
  • the core yams 16 As the core yams 16 are run through the cover 10, 10', 10", 10'", 10"", 10'"", 10""", the core yams 16 follow the path of the first plurality of cover yarns 12, 12", 12'", 12"", 12'"", 12'”"' based on a friction force between the plurality of core yams 16 and the proud first plurality of cover yarns 12, 12", 12'", 12"", 12'”", 12””", thereby twisting the core yarns 16 in a generally helical pattern within the cover 10, 10', 10", 10'", 10"", 10'"", 10""" and increasing the strength of the roundsling 18, 18', 18", 18'", 18”", 18'"", 18'"'"'", compared to untwisted core yams.
  • the core yarns 16 are run through the cover 10, 10', 10", 10'", 10"", 10'"", 10""" such that they follow the pattern of the first plurality of core yarns 16 to orient the plurality of core yarns 16 in the helical pattern within the braided cover 10, 10', 10", 10"', 10"", 10'"", 10""".
  • the core yarns 16 are not limited to following exactly the pattern of the first plurality of cover yams 12, 12", 12"', 12"", 12'"", 12""” and may twist to a lesser extent than the orientation and pattern of the first plurality of cover yams 12, 12", 12'", 12"", 12"'", 12'""' on the cover 10, 10', 10", 10'", 10"", 10'"", 10""".
  • the friction force urging the twist of the core yarns 16 generally does not produce the same orientation of the core yarns 16 as the specific orientation of the first plurality of yarns 12, 12", 12'", 12"", 12'"", 12""” with the braid angle A, A', A", A'", A"", A'"", A”"” measured relative to the braid axis 10a, 10a', 10a", 10a"', 10a'"', 10a'"", 10a""”.
  • the twist of the core yarns 16 in the helical pattern is generally oriented greater than parallel to the braid axis 10a, 10a', 10a", 10a'", 10a"", 10a'"", 10a""" and less than the braid angle A, A', A", A'", T e core y arns 16 generally follow the pattern of the first plurality of yarns 12, 12", 12'", 12”", 12'"", 12""” based on the frictional interaction between the plurality of core yarns 16 and the first plurality yarns 12, 12", 12'", 12"", 12'"", 12""" as the plurality of core yarns 16 are run through the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""".

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  • Manufacturing & Machinery (AREA)
  • Textile Engineering (AREA)
  • Braiding, Manufacturing Of Bobbin-Net Or Lace, And Manufacturing Of Nets By Knotting (AREA)

Abstract

A roundsling for lifting heavy loads includes a plurality of core yarns configured to bear the heavy load and a braided cover constructed of a plurality of cover yarns. The plurality of core yarns is constructed of a polymeric material. The plurality of cover yarns includes a first plurality of yarns and a second plurality of yarns. The first plurality of yarns has a first linear density and the second plurality of yarns has a second linear density. The first linear density is greater than the second linear density. The plurality of core yarns is oriented in a helical pattern within the braided cover.

Description

TITLE OF THE INVENTION
Braided Cover for Roundsling Having Twist in Core Yarns and Related Method
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S. Provisional Patent Application No. 63/538,331, filed September 14, 2023 and titled, “Braided Cover for Roundsling Having Twist in Core Yarns and Related Method,” the entire contents of which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] Synthetic fiber roundslings have been used in industry for a number of years for lifting loads in industrial applications such as manufacturing, construction, cargo handling, and many other applications where low weight, flexibility, versatility, strength and corrosion resistance are desired. Constructing roundslings from synthetic fibers provides advantages compared to traditional steel wire rope rigging including significantly lower weight, enhanced flexibility, and faster rigging time.
[0003] Synthetic fiber roundslings include a woven protective cover and a loadbearing core constructed of individual yarns. The load-bearing core yarns generally carry the force applied to the sling, while the cover provides structure and protection for the roundsling. The woven protective cover of prior art roundslings is relatively rigid for a fabric such that the tubular cover does not readily flex to accommodate a variable number of core strands leaving slack in the woven protective cover and empty space between the woven protective cover and the core strands. In large prior art roundslings that carry significant loads, the woven protective cover may require a wrap along its length to reduce the diameter of the prior art roundsling for ready connection to rigging hardware, which has a connection hook or joint accommodating only a limited size or diameter.
[0004] The protective roundsling covers include synthetic fibers that are constructed into a tubular form using manufacturing methods including, but not limited to, weaving, braiding, or knitting. The cover provides structure to the roundsling by constraining the load bearing core yarns in the correct configuration and geometry. The cover also protects the core yarns from damage from a number of factors including physical (e.g, cutting, snagging, and abrasion), ultraviolet degradation (from sunlight or artificial sources), chemical attack and other external irritants.
[0005] The load-bearing core yarns are typically constructed from synthetic fibers or strands that are formed into a bundle using manufacturing methods including, but not limited to, twisting, braiding, or stranding. Synthetic round slings may be made by winding the core yarns in an endless loop into the tubular protective cover. The winding is typically performed using a powered drive roller on one end and an unpowered idler roller or fixed roller on the other. The rollers are set a certain distance apart to produce the desired length of the roundsling. The desired capacity of the sling is achieved by winding multiple revolutions of core yarns into the cover. The total capacity of the sling is determined by multiplying the load-bearing capacity of one core yarn by how many total yams are included in the sling or roundsling. This value is then divided by a design factor (sometimes referred to as safety factor) to arrive at a rated working load. The more core yams that are contained in the protective cover, the greater the rated working load when comparing the same type of core yarns, and the greater the diameter or cross- sectional size of the core yarn bundle that the protective cover must accommodate. Once the desired number of core yarns are wound into the protective cover, the yam is cut and secured within the protective cover. The ends of the tubular protective cover are bound together to enclose the plurality of core yarns, thereby create the roundsling.
[0006] The process of adding additional core yams to increase load bearing capacity reaches certain limitations as the slings grow to larger sizes and capacities. This is because, in practice, the tension of each core yarn is not precisely controlled, leading to an imbalance in load sharing between the strength members or the core yams in the load bearing core. When the sling is loaded, the tighter strands or core yarns hold or carry a higher percentage of the total force applied to the sling compared to the looser strands or core yams and the tighter core yarns will fail first when brought to the breaking load of the sling. The looser or less-tensioned strands or core yarns will, therefore, not fully contribute to the load-bearing capacity of the sling at the time of failure. When the initial tighter strands or core yarns break, there is a rapid process of the next most tensioned strands or core yarns taking the load then failing until the entire load bearing core and sling may fail, although the slings are generally not loaded to failure, but well below failure under a factor of safety in operation, such that failure is only achieved during testing. Roundsling manufacturers may compensate for this loss in strength efficiency by adding additional load-bearing fibers, strands or core yearns beyond what would otherwise be required, thereby increasing the total strength of the roundsling and increasing the diameter or cross-section of the core yarns and requiring a larger tubular protective cover. This amount of additional fiber or core yarn that is added may be referred to as an efficiency or realization factor.
[0007] It is known that twisting or stranding fibers together when manufacturing fiber ropes results in an increased strength efficiency of the rope. The twisting or stranding process equalizes the tensions between the component fibers, allowing greater loadsharing when the finished rope or sling is placed under tension because there is a reduced tendency to have tighter and looser fibers in the rope under loading. Using traditional technologies, the nature of building a synthetic fiber roundsling or sling precludes the possibility of twisting the load-bearing core yarns together, thereby resulting in the potentially unbalanced loading of the individual core yams during use. The fibers or core yarns in a prior art roundsling are not twisted or stranded because the process requires each of the component strength members to be loaded onto separate reels or bobbins and placed into rotating machinery designed to form a rope or sling, which is not possible with the roundsling manufacturing process with the drive and fixed rollers. When a roundsling is made using conventional technology, the component strength member is fed directly into the cover, precluding this twisting or stranding.
[0008] It would be desirable to design, implement and deploy a roundsling having twisted or stranded core fibers or core yams to improve the load distribution on each of the fibers or core yarns during loading. The preferred invention addresses the described deficiencies of the prior art roundslings, particularly by twisting or stranding the core fibers or core yarns by incorporating a novel braided protective cover.
BRIEF SUMMARY OF THE INVENTION
[0009] Briefly stated, a preferred embodiment of the invention is directed to a roundsling for lifting heavy loads, wherein the roundsling includes a plurality of core yarns and a braided cover with a plurality of cover yarns. The plurality of cover yarns includes a first plurality of yams and a second plurality of yams. The plurality of core yarns is configured to bear the heavy load of the roundsling during use. The plurality of core yams are wrapped, stranded or twisted in a circular, spiral cylindrical or helix configuration and is constructed of a polymeric material. The first plurality of yams has a first linear density and the second plurality of yarns has a second linear density. The first linear density is greater than the second linear density. The plurality of core yarns is oriented in a helical pattern within the braided cover.
[0010] The preferred invention is comprised a synthetic roundsling including a helically laid load-bearing core yarn within a braided fiber protective cover. The roundsling is constructed such that the load-bearing core yarns are twisted or stranded as the core yarns are fed through the braided protective cover during manufacture or assembly. The core yarns are, therefore, positioned within the protective cover with a helical twist or pattern in an assembled configuration. The roundsling, which is manufactured in this way with the helically arranged core yarns, provides added strength efficiency compared to a roundsling manufactured using traditional methods, wherein the core yarns of the traditional or prior art roundsling are not twisted or are arranged generally linear or parallel to each other in the core of the roundsling within the woven protective cover.
[0011] The synthetic roundsling of the preferred embodiment has a cover made of synthetic fibers that are braided into an elongated tube. The protective cover may be constructed of one or more synthetic fiber materials, including, but not limited to, ultra- high molecular weight polyethylene (UHMPE or HMPE, such as Dyneema® or Spectra®), aromatic polyesters (e.g., liquid crystal polymers (LCP) such as Vectran®), para-aramid (such as Kevlar®, Twaron®, or Technora®), meta-aramid (such as Nomex®), polyester, nylon, polypropylene or other polymeric or synthetic materials. The cover includes a plurality of yams, including a first plurality of yarns and a second plurality of yarns. The first plurality of yarns has a first linear density and the second plurality of yarns has a second linear density. The first linear density is greater than the second linear density. This configuration results in the first plurality of yarns being positioned proud of the second plurality of yarns in the braided cover. [0012] The synthetic roundsling has load-bearing core yams constructed of a plurality of core yarns or synthetic fibers formed into a strength member using twisting, braiding, or stranding. The core yearns may be made of one or more synthetic fiber materials, including, but not limited to, ultra-high molecular weight polyethylene (UHMPE or HMPE, such as Dyneema® or Spectra®), aromatic polyesters (e.g., liquid crystal polymers (LCP) such as Vectran®), para-aramid (such as Kevlar®, Twaron®, or Technora®), meta-aramid (such as Nomex®), polyester, nylon, polypropylene or other polymeric or synthetic materials. The core yarns are preferably twisted or stranded as the core yams are drawn through the preferred protective cover having the braided first and second plurality of yarns, wherein the first yarns have a greater linear density than a second linear density of the second plurality of yarns. In the braided configuration, the first plurality of yarns of the protective cover are proud of the second plurality of yams. [0013] A braid is defined by the number of carriers in the braiding machine used to make up the structure of the braid. Each carrier is loaded with a bobbin of fiber or yarn and the carriers travel in a pre-determined path to form the braided member. Common braiding machines in the cordage industry include models with twelve, sixteen, twenty- four, thirty-two, forty-eight and ninety-six carriers (12, 16, 24, 32, 48 and 96), although the machines are not so limited and may include more or less carriers depending on designer and user preferences and application requirements. Braiding machines with these other numbers of carriers may be used to construct a braided structure. Each carrier may hold one or more untwisted fibers, or one or more twisted yarns made up of fibers. Typically, half of the carriers hold yams that are twisted in the “S” direction, then are braided in the “Z” direction, and the other half hold yarns that are twisted in the “Z” direction then are braided in the “S” direction. However, it is possible to make a braid where all yams are untwisted, all twisted in one direction, or the “S” and “Z” yarns are reversed from the typical arrangement.
[0014] When one or more of the carriers that are braiding in one direction is loaded with yams that are larger than the yams in the other carriers, this creates a helical pattern of yarn that is raised higher than the other yams making up the braid or results in the larger yarns being positioned proud of the smaller yarns in the final braid. This state of being higher or more prominent than the other yams in a braid is sometimes referred to as “proud”. When core yams are run into a protective cover with a helical pattern of proud yarns, there is a frictional interaction between the inside surface of the braided protective cover and the core yams that are drawn through the tubular protective cover that causes the core yams to follow the pattern of the proud yarns and twist helically as the core yarns are wound into the cover. In the preferred embodiments, the thicker or first yarns have a linear density of approximately sixteen to sixty thousand denier (16,000 - 60,000 den) and the smaller or second yarns have a linear density of approximately eight to thirty thousand denier (8,000 - 30,000 den).
[0015] The larger yarns may comprise anywhere from one strand to half of the total strands in the braided cover. In the preferred embodiments, however, four to twenty -five percent (4-25%) of the total strands in the braided cover are preferably comprised of the larger yarns, while seventy -five to ninety-six percent (75-96%) of the total strands in the braided cover are comprised of the smaller yarns. All of the larger strands are preferably braided in the same direction, such as the S-direction or the Z-direction, so that the induced twisting force on the core yams during assembly urges the core yams in the same direction.
[0016] The larger yams of the protective cover may be nearly any percent larger than the rest of the yarns in the braid of the protective cover, however, in the preferred embodiment, the larger yarns are approximately double the size of the smaller yams but are not so limited.
[0017] Helically twisting the core yams within the braided cover, as driven by the cover having the proud larger yarns compared to the smaller yarns, may result in a twelve to fifteen percent (12-15%) increase in strength of the load-bearing core, although the strength increase is not limited to falling into this range. This increases core strength results in a sling that can lift a higher load while having a smaller diameter and lighter weight than slings without the twisted core yarns and is an improvement over techniques and structures constructed in the traditional manner without the helical twist in the cover, resulting in untwisted core yarns within the cover.
[0018] In an additional preferred embodiment, a roundsling for lifting heavy loads includes a plurality of core yams constructed of a polymeric material and a braided cover constructed of a plurality of cover yarns. The plurality of cover yarns includes a first plurality of yarns and a second plurality of yarns. The first plurality of yarns has a first linear density and the second plurality of yarns has a second linear density. The first linear density is greater than the second linear density. The plurality of cover yarns have an S-direction and a Z-direction. The first plurality of yarns is oriented only in the S- direction.
[0019] In a further preferred embodiment, a method of constructing a roundsling having a braided cover and a plurality of core yarns on a synthetic sling manufacturing apparatus includes securing the braided cover on the synthetic sling manufacturing apparatus. The braided cover is constructed of a first plurality of cover yarns oriented only in an S-direction and a second plurality of cover yarns oriented in the S-direction and a Z-direction with the first plurality of yarns being proud of the second plurality of yarns in the assembled configuration. The method also includes introducing a first core yarn of the plurality of core yarns into the braided cover, running the plurality of core yarns through the braided cover such that the plurality of core yarns follow a pattern of the first plurality of yarns to orient the plurality of core yarns in a helical pattern within the braided cover and connecting opposing ends of the braided cover to enclose the plurality of core yams within the braided cover.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0020] The foregoing summary, as well as the following detailed description of preferred embodiments of the roundsling and related method of the present application, will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the roundsling and the roundsling manufacturing method, there are shown in the drawings preferred embodiments. It should be understood, however, that the application is not limited to the precise arrangements and instrumentalities shown. In the drawings:
[0021] Fig. 1 illustrates side elevational views of two prior art individual core strands having a left-lay 5 (z.e., an “S” twist) and a right-lay 6 (z.t?., a “Z” twist), respectively;
[0022] Fig. 2 illustrates a side elevational view of a roundsling having a braided cover in accordance with a first preferred embodiment of the present invention; [0023] 2A illustrates a cross-sectional view of a portion of the braided cover of Fig.
2, taken along line 2A-2A of Fig. 2 wherein the core yams are shown as a monolithic structure for convenience and clarity;
[0024] Fig. 3 illustrates a side elevational view of a roundsling having a braided cover in accordance with a second preferred embodiment of the present invention;
[0025] Fig. 4A illustrates a side elevational view of a roundsling having a braided cover in accordance with a third preferred embodiment of the present invention;
[0026] Fig. 4B illustrates a side elevational view of a roundsling having a braided cover in accordance with a fourth preferred embodiment of the present invention;
[0027] Fig. 4C illustrates a side elevational view of a roundsling having a braided cover in accordance with a fifth preferred embodiment of the present invention;
[0028] Fig. 4D illustrates a side elevational view of a roundsling having a braided cover in accordance with a sixth preferred embodiment of the present invention;
[0029] Fig. 4E illustrates a side elevational view of a roundsling having a braided cover in accordance with a seventh preferred embodiment of the present invention; and [0030] Fig. 5 illustrates a top perspective view of a partially constructed roundsling positioned in a synthetic sling manufacturing machine, wherein a plurality of core yarns are fed into one of the preferred braided covers of Figs. 2-4E to define one of the preferred roundslings.
DETAILED DESCRIPTION OF THE INVENTION
[0031] Certain terminology is used in the following description for convenience only and is not limiting. Unless specifically set forth herein, the terms “a”, “an” and “the” are not limited to one element but instead should be read as meaning “at least one”. The words "right", "left", "lower" and "upper" designate directions in the drawings to which reference is made. The terminology includes the above-listed words, derivatives thereof and words of similar import.
[0032] It should also be understood that the terms “about,” “approximately,” “generally,” “substantially” and like terms, used herein when referring to a dimension or characteristic of a component of the preferred invention, indicate that the described dimension/characteristic is not a strict boundary or parameter and does not exclude minor variations therefrom that are functionally the same or similar, as would be understood by one having ordinary skill in the art. At a minimum, such references that include a numerical parameter would include variations that, using mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit.
[0033] Referring to Figs. 2-5F, preferred embodiments of the present invention are directed to an improvement compared to synthetic slings having opposing lays, such as the synthetic sling described in U.S. Patent No. 8,322,765 (“‘765 patent”) or a rifled cover technology that involves a helical twisting induced in the core yarns by the woven cover. The method in which the twisting of the synthetic sling is achieved in the ‘765 patent is a different mechanism compared to how core yams 16 are twisted within the braided cover 10 in the preferred embodiments of the present invention. In the method of the ‘765 patent, the twisting in the synthetic sling is induced by warp yams on the inner layer of the woven cover having a opposite twist as compared to the twisted core yarns being run into the tubular cover.
[0034] In a first preferred embodiment, the present invention is directed to a roundsling, generally designated 18, for lifting heavy loads. The roundsling 18 includes a plurality of core yams 16 configured to bear the heavy load during use. The core yarns 16 are constructed of a polymeric material. The core yams 16 of Fig. 2A are shown as a monolithic structure for convenience and clarity but are preferably comprised of bundles or the plurality of core yarns 16 that are twisted in a helical pattern, as is described herein. The roundsling 18 also includes a braided cover 10 constructed of a plurality of cover yarns, including a first plurality of yarns 12 and a second plurality of yarns 14. The first plurality of yarns 12 and the second plurality of yams 14 are shown in Fig. 2A as individual monolithic yams, but are not so limited and each of the individual yarns 12, 14 may be comprised of a bundle of filaments or strands that comprise the individual members of the first and second plurality of yarns 12, 14. The braided cover 10 has a tubular construction such that the core yarns 16 may be contained therein in an assembled or working configuration. The first plurality of yams 12 has a first linear density and the second plurality of yams 14 has a second linear density. The first linear density is greater than the second linear density. In the preferred embodiment, the first linear density is approximately two to six times (2-6X) greater than the second linear density. The plurality of core yams 16 is oriented in a helical pattern within the braided cover 10 in an assembled configuration.
[0035] The individual yams or bundles of the first plurality of yams 12 may have a first diameter DI and the individual yarns or bundles of the second plurality of yarns 14 may have a second diameter D2, wherein the first diameter DI is greater than the second diameter D2. The first diameter DI may be approximately fifty hundredths of an inch to one hundred hundredth of an inch (0.050 - 0.100”) or one and twenty-seven hundredths millimeters to two and fifty-four hundredth millimeters (1.27 - 2.54 mm) and the second diameter D2 may be approximately ninety thousands inches to one hundred seventh-five thousands inches (0.90 - 0.175”) or two and twenty-nine hundredths to four and forty- five hundredths millimeters (2.29 - 4.45 mm). The first and second diameters DI, D2 are not limited to these described ranges, but these size ranges are preferred for the braided cover 10 of the preferred embodiments but may be otherwise designed and configured depending on designer preferences, specific applications of the roundsling 18 or other design factors.
[0036] In the preferred embodiments, the core yarns 16 are constructed of a polymeric material. The polymeric material of the core yarns 16 may be comprised of ultra-high molecular weight polyethylene (UHMPE or HMPE, such as Dyneema® or Spectra®), aromatic polyesters (e g., liquid crystal polymers (LCP) such as Vectran®), para-aramid (such as Kevlar®, Twaron®, or Technora®), meta-aramid (such as Nomex®), polyester, nylon, polypropylene or other polymeric or synthetic materials. The polymeric material of the core yarns 16 provides a relatively high strength to weight ratio, durability, corrosion resistance and other advantages compared to alternative core materials. The core yarns 16 are not limited to the specific polymeric materials described herein and may be comprised of nearly any material that is able to take on the general size and shape of the core yams 16, withstand the normal operating conditions of the core yarns 16 and perform the preferred functions of the core yams 16, as described herein. The plurality of cover yarns 12, 14 are similarly, preferably constructed of a polymeric material, wherein the polymeric material of the cover yarns 12, 14 is preferably comprised of ultra-high molecular weight polyethylene, aromatic polyester, para-aramid, meta-aramid, polyester, nylon, polypropylene or other polymeric or synthetic materials. The plurality of cover yarns are not limited to the specific polymeric materials described herein and may be comprised of nearly any material that is able to take on the general size and shape of the plurality of cover yams 12, 14, withstand the normal operating conditions of the plurality of cover yarns 12, 14 and perform the preferred functions of the plurality of cover yarns 12, 14, as described herein.
[0037] In the preferred invention, the direction of twist of the yarns of the cover 10 and the plurality of core yarns 16 is irrelevant. In the preferred invention, the helical path of the core yarns 16 is driven by the direction that the larger sized or first plurality of yarns 12 are braided into the cover 10 compared to the smaller sized or second plurality of yarns 14 that comprise the remaining yams of the plurality of cover yarns in the braided cover 10. The larger sized or first plurality of yarns 12 of the braided cover 10 induce a twist into the core yarns 16 as the core yams 16 are drawn or driven through the braided cover 10 during assembly utilizing the sling manufacturing machine 30. Since the twist induced into the core yarns 16 does not depend on the interaction of the opposite twists of the core yarns and the woven cover of the ‘765 patent, the preferred invention can induce twist in other types of core yarns 16, for example, ones that are made with a braiding process or nearly any other variety of core yarns 16, regardless of their direction of twist.
[0038] The preferred invention also differs from the synthetic sling of ‘765 patent in the construction of the protective jacket or cover 10. The jacket or cover of the ‘765 patent is necessarily constructed using a weaving process so that all of the twisted warp yarns are running along the longitudinal direction of the cover. These yarns of the cover described in the ‘765 patent must make contact with the twisted core yarn as they enter the cover. In the preferred invention, the cover 10 is constructed using a braiding process using the plurality of cover yarns 12, 14. The braiding process allows the helical pattern to be formed with the larger or first plurality of yarns or strands 12 and the smaller or second plurality yarns or strands 14. A woven roundsling cover, such as the cover of the ‘765 patent, is generally fixed into the width that is established when the jacket is manufactured. However, the braided tube or cover 10 of the preferred embodiment can expand and contract depending on the size of the core yarn 16 or the number of core yarns 16 that is inside the cover 10. This means that in the preferred invention, the braided cover 10 may to conform to the size or volume of the plurality of core yarns 16 during use, further reducing the final diameter of the roundsling 18 and making it easier to fit the roundsling 18 into smaller lifting points, thereby providing an advantage over the roundsling of the ‘765 patent. Specifically, the braided cover 10 of the preferred embodiments provides flexibility to confirm to different sizes and volumes of the plurality of core yams 16, while the woven cover of the roundsling of the ‘765 patent is more rigid, resulting in assemblies where empty space may be present between the internal surface of the cover and the core yarns.
[0039] Referring to Fig. 2, the first preferred embodiment of the roundsling 18 includes the cover 10 with a forty-eight carrier (48-carrier) braid having one yarn per carrier where the dark or first plurality of yarns or strands 12 are the larger yams or strands 12 or the strands having the increased or greater first linear density when compared to the smaller or reduced second linear density of the second plurality of yarns 14. The first plurality of strands 12 are positioned proud of the second plurality of strands 14 in the braided structure of the cover 10, which creates a helical path in the S direction (left hand lay) comprised of two (2) strands out of the total forty-eight (48) strands in the braided cover 10. In this first preferred embodiment, the light or second plurality of yams or strands 14 are the smaller strands or the strands having the second linear density or the smaller linear density compared to the relatively larger linear density of the first plurality of yarns or strands 12.
[0040] Referring to Fig. 3, a second preferred embodiment of the roundsling 18' includes similar features compared to the features of the first preferred roundsling 18. The same reference numerals are utilized to identify the same features of the second preferred embodiment with a prime symbol (') utilized to distinguish the features of the second preferred roundsling 18' from the features of the first preferred roundsling 18. The second preferred roundsling 18' includes a braided cover 10' with a twenty -four carrier (24-carrier) braid having two yarns per carrier where the first plurality of strands or yams 12' are the larger strands or yarns 12' having the greater first linear density when compared to the second plurality of strands or yarns 14', which are the smaller strands or yarns 14', having the second smaller linear density. One-half of the strands braided in the S direction (left hand lay) are the first plurality of yarns 12' or fifty percent (50%) of the total twenty -four (24) strands or yarns 12', 14' and the second plurality of strands or yarns 14' or smaller strands or yarns 14' comprise fifty percent (75%) of the total strands 12', 14' of the cover 10'. In the preferred embodiments, the first plurality or larger yarns 12, 12' comprises five to fifty percent (5-50%) of the cover yams 12, 12', 14, 14' oriented in the S-direction of the braided cover 10, 10'.
[0041] The first plurality or larger yarns 12, 12' of the cover 10, 10' may comprise anywhere from one strand to half of the total strands in the braided cover 10, 10'. The first plurality or larger yarns 12, 12' may comprise four to twenty-five percent (4-25%) of the total strands in the braided cover 10, 10', while the second plurality or smaller yams 14, 14' may comprise seventy-five to ninety-six percent (75-96%) of the total strands in the braided cover 10, 10'. The first plurality or larger strands or yams 12, 12' are preferably braided in the same direction, such as the S-direction or the Z-direction, so that the induced twisting force on the core yams 16 during assembly urges the core yarns 16 to twist in the same direction. In the preferred embodiments, the first plurality or larger strands or yarns 12, 12' is oriented only in the S-direction in the braided cover 10, 10' and the second plurality of yarns 14, 14' is oriented in both the S-direction and the Z- direction.
[0042] The braided cover 10, 10' preferably defines a braid axis 10a, 10a' and the plurality of first or larger yams 12, 12' extend at a braid angle A, A' relative to the braid axis 10a, 10a'. The braid angle A, A' may be approximately twenty to forth degrees (20- 40°, thirty to thirty-five degrees (30-35°) or nearly any acute angle that facilitates twisting of the plurality of core yarns 16, 16' during assembly of the roundsling 18, 18'. [0043] Referring to Figs. 2-4F, first, second, third, fourth, fifth, sixth and seventh preferred embodiments of the roundsling 18, 18', 18", 18'", 18"", 18'"", 18""" may be constructed having the larger or first plurality of strands or yarns 12, 12', 12", 12'", 12"", 12"'", 12""” in differing percentages compared to the smaller or second plurality of strands or yarns 14, 14', 14", 14'", 14'"', 14'"", 14""" in the total strands of the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""". The third, fourth, fifth, sixth and seventh preferred embodiments of the roundsling 18", 18'", 18"", 18'"", 18""" have similar or the same features compared to the features of the first and second preferred roundslings 18, 18'. The same reference numerals are utilized to identify the same or similar features of the third, fourth, fifth, sixth and seventh preferred embodiments of the roundsling 18", 18'", 18"", 18'"", 18""" with double, triple, four, five and six prime symbols ("), ("'),
Figure imgf000015_0001
(""") utilized to distinguish the features of the third, fourth, fifth, sixth and seventh preferred embodiments from the features of the first and second preferred roundslings 18, 18', respectively.
[0044] Referring to Figs. 4A-4F, in the first, third, fourth, fifth, sixth and seventh preferred embodiments of the cover 10, 10", 10'", 10"", 10'"", 10'"'", the first preferred embodiment of the cover 10 has the least percentage of larger strands 12 in the braid while the seventh preferred cover 10""" has the most or highest percentage of larger strands 12'""', with the third, fourth, fifth and sixth preferred covers 10", 10'", 10"", 10'"" having increasing percentages of larger strands 12", 12'", 12"", 12'"" between the first and seventh preferred covers 10, 10""". These preferred embodiments of the cover 10, 10", 10'", 10"", 10"'", 10'"'" illustrate that the cover 10, 10", 10'", 10"", 10'"", 10""" may be constructed having various percentages of larger and smaller strands 12, 12", 12'", 12"", 12'"", 12""", 14, 14", 14'", 14"", 14'"", 14""" with the preferred construction and assembly method of the invention described herein. The covers 10, 10', 10", 10'", 10'"', 10'"", 10""" of the preferred embodiments also define the braid angles A, A', A", A'", A"", A'"", A”"" measured relative to the braid axis 10a, 10a', 10a", 10a'", 10a"", 10a'"", 10a""".
[0045] Referring to Fig. 5, a sling manufacturing machine 30 may be utilized to construct or manufacture the roundsling 18", 18"', 18"”, 18””', 18”"” by positioning the core yams 16 within the braided cover 10, 10", 10'", 10"", 10'"", 10""". The sling manufacturing machine 30 may operate similarly and have similar features to the tensioning apparatus for synthetic sling manufacturing described in U.S. Patent No.
10,113,267 (‘“267 patent"), which is incorporated herein by reference in its entirety. The sling manufacturing machine 30 includes a drive roller 38 that draws the individual strands or yams or multiple strands or yarns of the plurality of core yarns 16 into the cover 10, 10", 10'", 10"", 10""', 10""". The plurality of core yarns 16 are comprised of continuous yarns or strands that wrap around itself within the cover 10, 10', 10", 10"', 10"", 10'"", 10""" a predetermined number of times depending on the size or rating of the roundsling 18, 18', 18", 18'", 18'"', 18'"", 18""" and the number of individual strands or yams driven by the drive roller 38. The roundsling 18, 18', 18", 18'", 18"", 18"'", 18'""' is manufactured by selecting the appropriate cover 10, 10', 10", 10'", 10"", 10'"", 10""", cutting the cover 10, 10', 10", 10'", 10”", 10'"", 10""" and connecting a cut first end 10b of the cover 10, 10', 10", 10'", 10"", 10'"", 10""" to a cross-bar 83 of the sling manufacturing machine 30. The plurality of core yams 16 are drawn through the inside of the cover 10, 10', 10", 10'", 10"", 10'"", 10""" and the proud larger strands 12, 12", 12'", 12"", 12'"", 12""" drive the core yarns 16 to twist within the cover 10, 10', 10", 10'", 10"", 10'"", 10""".
[0046] During operation or manufacturing of the roundsling 18, 18', 18", 18'", 18"", 18"'", 18'""', when the cover 10, 10', 10", 10'", 10"", 10'"”, 10'""' includes the helical pattern with the raised larger strands 12, 12", 12'", 12"", 12'"", 12""" and the lower or smaller strands 14, 14", 14'", 14"", 14"'", 14'"'", the state of the larger strands 12, 12", 12'", 12"", 12'"", 12""" being higher or more prominent than the smaller strands 14, 14", 14'", 14"", 14'"", 14""" in the braid may be referred to as “proud”. When the core yarns 16 are run into the cover 10, 10', 10", 10"', 10”", 10'"", 10""" with the helical pattern of the larger strands or first plurality of yearns 12, 12", 12"', 12"", 12'"", 12'""', there is a frictional interaction that causes the core yarns 16 to follow the pattern of the larger strands or first plurality of yams 12, 12", 12'", 12"", 12'"", 12""" to twist the core yarns 16 helically as they are wound into the cover 10, 10', 10", 10'", 10"", 10'"", 10""". In the preferred embodiments, the thicker or larger strands 12, 12", 12'", 12"", 12"'", 12""" have a linear density of approximately sixteen to sixty thousand denier (16,000 - 60,000 den) and the smaller yams 14, 14", 14'", 14"", 14'"", 14""", have a linear density of approximately eight to thirty thousand denier (8,000 - 30,000 den).
[0047] In operation, the roundsling 18, 18', 18", 18'", 18"", 18'"", 18""" with the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""" and plurality of core yarns 16 is constructed or assembled partially using the sling manufacturing machine 30. The braided cover 10, 10', 10", 10"', 10"", 10'"", 10""" is constructed of the first plurality of cover yams 12, 12", 12'", 12"", 12'"", 12""" and the second plurality of cover yarns 14, 14", 14'", 14"", 14'"", 14""", wherein the first plurality of cover yarns 12, 12", 12'", 12"", 12'"", 12""" is oriented only in the S-direction and the second plurality of cover yarns 14, 14", 14'", 14'"', 14'"", 14""" is oriented in the S-direction and the Z-direction with the first plurality of yarns 12, 12", 12'", 12'"', 12'"", 12""" being proud of the second plurality of yams 14, 14", 14'", 14"", 14'"", 14""" in the assembled configuration.
[0048] The preferred roundsling 18, 18', 18", 18'", 18"", 18"'", 18""" is assembled by securing a first end 10b of the tubular cover 10, 10', 10", 10'", 10"", 10'"", 10""" to the cross bar 83 of the sling manufacturing apparatus or the sling manufacturing machine 30. A first core yarn 16 of the plurality of core yarns 16 is introduced into the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""" and the plurality of core yams 16 are run or pulled through the braided cover 10, 10', 10", 10'", 10"", 10'"”, 10"'"' such that the plurality of core yarns 16 follows a patterns of the first plurality of cover yarns 12, 12", 12'", 12"", 12'"", 12""" to orient the plurality of core yarns 16 in a helical pattern within the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""". The plurality of core yams 16 are preferably fed from spools over the drive roller 38, into the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""", around a follower roller (not shown), out of a second end 10c of the cover 10, 10', 10", 10'", 10"", 10'"", 10”"" and back over the drive roller 38. The sling manufacturing machine 30 drives the plurality of core yarns 16 a predetermined number of revolutions to position the predetermined number of the plurality of core yarns 16 into the cover 10, 10', 10", 10'", 10"", 10'””, 10”””. As the core yams 16 are run through the cover 10, 10', 10", 10'", 10"", 10'"", 10""", the core yams 16 follow the path of the first plurality of cover yarns 12, 12", 12'", 12"", 12'"", 12'""' based on a friction force between the plurality of core yams 16 and the proud first plurality of cover yarns 12, 12", 12'", 12"", 12'"", 12""", thereby twisting the core yarns 16 in a generally helical pattern within the cover 10, 10', 10", 10'", 10"", 10'"", 10""" and increasing the strength of the roundsling 18, 18', 18", 18'", 18”", 18'"", 18'"'", compared to untwisted core yams. The core yarns 16 are run through the cover 10, 10', 10", 10'", 10"", 10'"", 10""" such that they follow the pattern of the first plurality of core yarns 16 to orient the plurality of core yarns 16 in the helical pattern within the braided cover 10, 10', 10", 10"', 10"", 10'"", 10""".
[0049] The core yarns 16 are not limited to following exactly the pattern of the first plurality of cover yams 12, 12", 12"', 12"", 12'"", 12""" and may twist to a lesser extent than the orientation and pattern of the first plurality of cover yams 12, 12", 12'", 12"", 12"'", 12'""' on the cover 10, 10', 10", 10'", 10"", 10'"", 10""". The friction force urging the twist of the core yarns 16 generally does not produce the same orientation of the core yarns 16 as the specific orientation of the first plurality of yarns 12, 12", 12'", 12"", 12'"", 12""" with the braid angle A, A', A", A'", A"", A'"", A""" measured relative to the braid axis 10a, 10a', 10a", 10a"', 10a'"', 10a'"", 10a""”. The twist of the core yarns 16 in the helical pattern is generally oriented greater than parallel to the braid axis 10a, 10a', 10a", 10a'", 10a"", 10a'"", 10a""" and less than the braid angle A, A', A", A'",
Figure imgf000018_0001
T e core yarns 16 generally follow the pattern of the first plurality of yarns 12, 12", 12'", 12”", 12'"", 12""" based on the frictional interaction between the plurality of core yarns 16 and the first plurality yarns 12, 12", 12'", 12"", 12'"", 12""" as the plurality of core yarns 16 are run through the braided cover 10, 10', 10", 10'", 10"", 10'"", 10""". Once the predetermined number of rotations or revolutions of core yarns 16 is positioned within the braided cover 10, 10', 10", 10'", 10"", 10'"", 10”"", the plurality of core yarns 16 extending from the spools is cut and bound to the helically twisted core yams 16 in the cover 10, 10', 10", 10"', 10'"', 10'"", 10”"" and the first and second ends 10b, 10c of the cover 10, 10', 10", 10'", 10"", 10'"", 10""" are connected to enclose the plurality of core yarns 16 within the cover 10, 10', 10", 10'", 10"", 10'"”, 10""".
[0050] It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the present description.

Claims

CLAIMS I/We claim:
1. A roundsling for lifting heavy loads, the roundsling comprising: a plurality of core yams configured to bear the heavy load, the plurality of core yarns constructed of a polymeric material; and a braided cover constructed of a plurality of cover yarns, the plurality of cover yarns including a first plurality of yarns and a second plurality of yarns, the first plurality of yarns having a first linear density and the second plurality of yams having a second linear density, the first linear density being greater than the second linear density, the plurality of core yams oriented in a helical pattern within the braided cover.
2. The roundsling of claim 1, wherein the first linear density is approximately sixteen to sixty thousand denier and the second linear density is approximately eight to thirty thousand denier.
3. The roundsling of claim 1, wherein the polymeric material is selected from the group consisting of ultra-high molecular weight polyethylene, aromatic polyester, para-aramid, meta-aramid, polyester, nylon and polypropylene.
4. The roundsling of claim 1, wherein the cover is constmcted of a material selected from the group consisting of ultra-high molecular weight polyethylene, aromatic polyester, para-aramid, meta-aramid, polyester, nylon, and polypropylene.
5. The roundsling of claim 1, wherein the first plurality of yarns are positioned proud relative to the second plurality of yarns in the braided cover.
6. The roundsling of claim 1, wherein the first plurality of yarns comprises four to twenty-five percent and the second plurality of years comprises seventy-five to ninety- six percent of the plurality of cover yarns.
7. The roundsling of claim 1, wherein the first plurality of yarns have a linear density of approximately sixteen thousand to sixty thousand denier.
8. The roundsling of claim 1, wherein the second plurality of yarns have a linear density of approximately eight thousand to sixty thousand denier.
9. The roundsling of claim 1, wherein the braided cover defines a braid axis, the plurality of first yarns extending at a braid angle relative to the braid axis.
10. The roundsling of claim 9, wherein the braid angle is approximately twenty to forty degrees.
11. The roundsling of claim 9, wherein the braid angle is approximately thirty to thirty-five degrees.
12. The roundsling of claim 1, wherein the braided cover has a tubular configuration.
13. The roundsling of claim 1, wherein the wherein the first plurality of yarns are oriented only in an S-direction in the braided cover, the second plurality of yarns oriented in both the S-direction and a Z-direction in the braided cover.
14. The roundsling of claim 13, wherein the first plurality of yams comprises five to fifty percent of the cover yarns oriented in a S-direction of the braided cover.
15. A roundsling for lifting heavy loads, the roundsling comprising: a plurality of core yams constructed of a polymeric material; and a braided cover constructed of a plurality of cover yarns, the plurality of cover yarns including a first plurality of yarns and a second plurality of yarns, the first plurality of yarns having a first linear density and the second plurality of yams having a second linear density, the first linear density being greater than the second linear density, the plurality of cover yams having an S-direction and a Z-direction, the first plurality of yarns oriented only in the S-direction.
16. The roundsling of claim 15, wherein the second plurality of yarns are oriented in the S-direction and the Z-direction.
17. The roundsling of claim 15, wherein the plurality of core yarns are positioned within the braided cover in an assembled configuration, the plurality of core yarns oriented in a helical pattern in the assembled configuration.
18. The roundsling of claim 15, wherein the first linear density is approximately two to six times greater than the second linear density.
19. A method of constructing a roundsling having a braided cover and a plurality of core yarns on a synthetic sling manufacturing apparatus, the braided cover constructed of a first plurality of cover yams oriented only in an S-direction and a second plurality of yarns oriented in the S-direction and a Z-direction with the first plurality of yarns being proud of the second plurality of yams in the assembled configuration, the method comprising the steps of: securing the braided cover on the synthetic sling manufacturing apparatus; introducing a first core yam of the plurality of core yarns into the braided cover; running the plurality of core yarns through the braided cover such that the plurality of core yams follow a pattern of the first plurality of yarns to orient the plurality of core yarns in a helical pattern within the braided cover; and connecting opposing ends of the braided cover to enclose the plurality of core yarns within the braided cover.
20. The method of claim 19, wherein the core yarns follow the pattern of the first plurality of yarns based on frictional interaction between the plurality of core yarns and the first plurality of yarns as the plurality of core yarns are run through the braided cover.
PCT/US2024/045802 2023-09-14 2024-09-09 Braided cover for roundsling having twist in core yarns and related method WO2025058978A1 (en)

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US20090107573A1 (en) * 2007-10-31 2009-04-30 St Germain Dennis Apparatus for making slings
US7926859B2 (en) * 2007-10-31 2011-04-19 Slingmax, Inc. Synthetic sling whose component parts have opposing lays
US20150152595A1 (en) * 2012-07-17 2015-06-04 Dsm Ip Assets B.V. Abrasion resistant product
US20170254002A1 (en) * 2016-03-04 2017-09-07 Slingmax, Inc. Tensioning apparatus for synthetic sling manufacturing apparatus and method
WO2020041629A1 (en) * 2018-08-23 2020-02-27 Actuant Corporation Braided rope structure

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5060466A (en) * 1988-10-31 1991-10-29 Tokyo Rope Mfg. Co. Ltd. Composite rope and manufacturing method for the same
US20090107573A1 (en) * 2007-10-31 2009-04-30 St Germain Dennis Apparatus for making slings
US7926859B2 (en) * 2007-10-31 2011-04-19 Slingmax, Inc. Synthetic sling whose component parts have opposing lays
US20150152595A1 (en) * 2012-07-17 2015-06-04 Dsm Ip Assets B.V. Abrasion resistant product
US20170254002A1 (en) * 2016-03-04 2017-09-07 Slingmax, Inc. Tensioning apparatus for synthetic sling manufacturing apparatus and method
WO2020041629A1 (en) * 2018-08-23 2020-02-27 Actuant Corporation Braided rope structure

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