LONG LIVED SYNTHETIC ROPE FOR POWERED BLOCKS

Abstract

Disclosed is a method for producing a high strength synthetic strength member containing rope and a resultant rope, comprising multiple layers of twisted and braided yarns, wherein individual sheaths enclosing individual strands are of a material such as HMPE, PTFE or UHMWPE with a lower decomposition temperature than the material of said strands being aramid, the method comprising subjecting parts of the rope to heat and tension thereby pre-stretching and creating a non-uniform or non-round shape of said strands, further choosing a combination of braid and twist angles as well as braid compressive forces to accommodate specific strength and elongation relation between the individual rope layers.

Claims

1-57. (canceled)

58. A method for forming a synthetic rope (1), the method having steps of: a) providing a core (3) formed of at least a first synthetic substance and selecting for the first synthetic substance a thermoplastic substance; b) enclosing the core within at least a flow shield capable of retaining within the flow shield at least most of the first synthetic substance when the first synthetic substance is in a semi-liquid phase; c) providing a plurality of individual primary strands (19) formed of fibers formed of at least a second synthetic substance and selecting for the fibers fibers including Aramid fibers; the method characterized by steps of: d) forming from a third synthetic substance at least a plurality of inner individual sheaths (21) with a braided construction, wherein at least one inner individual sheath (21) formed with a braided construction is formed about and encloses at least one of the individual primary stands (19) formed of the second synthetic substance, so that at least some of the individual primary strands (19) formed of the second synthetic substance are each enclosed by a respective one of the inner individual sheaths (21) formed of the third synthetic substance, wherein the third synthetic substance forming at least some of the inner individual sheaths (21) has a lower decomposition temperature than does the second synthetic substance; e) next, forming a hollow braided strength member (7) around the core (3) from a plurality of the individual primary strands (19), wherein at least some of the individual primary strands (19) used in forming the hollow braided strength member (7) have at least one inner individual sheath (21); f) subjecting the strength member to tension and heat so as to cause the core to experience a non-solid phase and so as to cause the strength member and the core to become compacted and elongated; followed by cooling both at least the strength member and the core under tension so as to cause the strength member and the core to become permanently compacted and permanently elongated; and g) enclosing the strength member within an outer sheath (8), wherein the synthetic strength membered rope is permanently compacted and permanently elongated having a strength member formed of strands formed of Aramid fibers and other fibers that are less heat tolerant compared to Aramid fibers, the synthetic strength membered rope exhibiting a longer service life and improved tolerance to bend fatigue induced heats when used with blocks and/or sheaves in comparison to a rope having a strength member formed purely of Aramid fibers.

59. The method of claim 58 further comprising the step of selecting for the third synthetic substance a substance that is less bristle than is the second synthetic substance.

60. The method of claim 58 further comprising the step of selecting to form the braided construction of at least one of the inner individual braided primary sheaths (21) from fibers.

61. The method of claim 60 further comprising the step of selecting fibers comprising HMPE.

62. The method of claim 4 further comprising the step of selecting fibers comprising PTFE.

63. The method of claim 61 further comprising the step of selecting to also form the outer sheath (8) with a hollow braided construction, and by selecting to adhere the hollow braided strength member (7) to the hollow braided outer sheath (8) by steps of: selecting to situate at least a fourth synthetic substance in a flowable phase onto the exterior surface of a plurality of the inner individual braided sheaths (21) formed of the third synthetic substance where such fourth synthetic substance is, when in a set and/or solid state, an elastic and adhesive substance; followed by forming a hollow braided outer sheath (8) about the hollow braided strength member (7) and selecting to form the hollow braided outer sheath (8) compressing against the exterior surfaces of at least portions of the plurality of the inner individual braided sheaths (21) formed of the third synthetic substance.

64. The method of claim 62 further comprising the step of selecting to also form the outer sheath (8) with a hollow braided construction, and by selecting to adhere the hollow braided strength member (7) to the hollow braided outer sheath (8) by steps of: selecting to situate at least a fourth synthetic substance in a flowable phase onto the exterior surface of several of the inner individual braided sheaths (21) formed of the third synthetic substance where such fourth synthetic substance is, when in a set and/or solid state, an elastic and adhesive substance; followed by forming a hollow braided outer sheath (8) about the hollow braided strength member (7) and selecting to form the hollow braided outer sheath (8) compressing against the exterior surfaces of at least portions of a plurality of the inner individual braided sheaths (21) of the third synthetic substance.

65. The method of claim 63 further comprising selecting to apply a constrictive force by a plurality of the inner individual. braided sheaths (21) to a plurality of the primary strands (19) that is a constrictive force that is sufficiently low so that a plurality the primary strands (19) is deformed during manufacturing of the rope and adopts a non-circular cross section in the finished rope product when viewed in a plane that is perpendicular to the long dimension of the rope.

66. The method of claim 64 further comprising selecting to apply a constrictive force by a plurality of the inner individual braided sheaths (21) to a plurality of the primary strands (19) that is a constrictive force that is sufficiently low so that a plurality of the primary strands (19) is deformed during manufacturing of the rope and adopts a non-circular cross section in the finished rope product when viewed in a plane that is perpendicular to the long dimension of the rope.

67. The method of claim 65 further comprising selecting to form a plurality of the inner individual braided sheaths (21) from flattened fibers.

68. The method of claim 66 further comprising selecting to form a plurality of the inner individual braided sheaths (21) from flattened fiber.

69. The method of claim 67 further comprising selecting to braid the sheaths (21) from the flattened fibers in such fashion that at least some of the flattened fibers are untwisted about their long axis along a section of the finished rope.

70. The method of claim 68 further comprising selecting to braid the sheaths (21) from the flattened fibers in such fashion that at least some of the flattened fibers are untwisted about their long axis along a section of the finished rope.

71. The method of claim 1 characterized by the further step of stranding the primary strands (19) directly from fibers and/or filaments.

72. The method of claim 59 characterized by the further step of stranding the primary strands (19) directly from fibers and/or filaments.

73. The method of claim 65 characterized by the further step of stranding the primary strands (19) directly r from fibers and/or filaments.

74. The method of 66 characterized by the further step of stranding the primary strands (19) directly from fibers and/or filaments.

75. The method claim 67 characterized by the further step of stranding the primary strands (19) directly from fibers and/or filaments.

76. The method of claim 11 characterized by the further step of stranding the primary strands (19) directly from fibers and/or filaments.

77. The method of claim 68 characterized by the further step of stranding the primary strands (19) directly from fibers and/or filaments.

78. The method of claim 69 characterized by the further step of stranding the primary strands (19) directly from fibers and/or filaments.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0036] FIG. 1 is a plan view of a portion of a rope of the present disclosure.

[0037] FIG. 2 is a view of a cross section of the Rope of the present disclosure taken along line A-A of FIG. 1.

[0038] FIG. 3 is an expanded detail view of a portion of the cross section of the rope of the present disclosure shown in FIG. 2 that is indicated by reference character B. The expanded detailed view includes a braided outer sheath of the rope of the present disclosure, a portion of the strength member of the rope of the present disclosure where such portion of the strength member is proximal the braided outer sheath, as well as associated structures.

[0039] FIG. 4 is a plan view depicting an individual primary rope strand several of which form the strength member.

[0040] FIG. 5 is a plan view depicting an alternative embodiment of an individual primary rope strand several of which form the strength member.

BEST MODE FOR CARRYING OUT THE DISCLOSURE

[0041] FIG. 2 and FIG. 3 illustrate essential constructional components of one of the most preferred embodiments for use with high tension powered blocks of the long lived synthetic rope for powered blocks of the present disclosure that is identified by the general reference character 1. FIG. 2 depicts a preferably thermoplastic shaped supportive core 3 enclosing an optional core 2 that can be an elongatable conductive structure capable of transmitting information and/or data, or that can be a lead core, or other, the shaped supportive core 3 being enveloped within a flow shield sheath 5. Strength member 7 encloses the combination of the shaped supportive core 3, its enveloping flow shield sheath 5 and its optional core 2. The strength member is formed of several individual primary strands 19. The various individual primary strands 19 preferably are of uniform construction, or of similar construction. Each of the individual primary strands 19 is enclosed within a distinct primary strand sheath 21. The individual primary strands 19 are each formed of fibres and/or filaments that are formed of the second synthetic substance, that preferably is an Aramid. Each of the distinct primary strand sheaths 21 are formed of the third synthetic substance, and preferably formed of either a wrapped tape of PTFE or a braided sheath formed of PTFE, HMPE or UHMWPE.

[0042] Exterior sheath 8 preferably is of a braided construction and is adhered to strength member 7 by elastic adhesive substance layer 9, that preferably is formed of a settable adhesive substance such as an adhesive polyurethane having a high elasticity and a high shear strength, such as a two or more component PUR. Preferably braided exterior sheath 8 is formed of multiple coverbraid strands 10 by use of a braiding machine, the coverbraid strands 10 preferably are of a laid construction. Preferably, there are thirty-two individual strands 10 forming the coverbraided exterior sheath 8, each strand 10 having between twenty-four to thirty-six UHMWPE or HMPE fibers in each strand, preferably of a abrasion resilient construction. However, any quantity of strands 10 forming the coverbraided exterior sheath 8 that provide sufficient wear resistance and strength transfer to the strength transfer to the strength member are useful, including but not limited to twenty-four, twenty-eight, thirty-six, forty-two, forty-eight, up to sixty-four and even much more. The braid tension on each strand 10 forming the coverbraided exterior sheath 8 during braiding operations is preferably about sixty-three kilogram, and can be from forty to one hundred sixty kilograms. Importantly, the braid tension on each strand forming a braided primary strand sheath 21 during braiding operations of any such braided primary strand sheath 21 when a braided sheath variant is selected for the primary strand sheaths 21 is lesser per strand forming a braided sheath 21 in comparison to the braid tension used per strand 10 during braiding operations when forming the coverbraided exterior sheath 8. The braid tension on each strand forming a braided primary strand sheath 21 during braiding operations of any such braided primary strand sheath 21 is preferably about seven kilograms, and can be from ten grams to thirty kilograms, though optionally it is nine times less than the braid tension used per strand 10 during braiding operations when forming the coverbraided exterior sheath 8, and is at least forty percent less.

[0043] Optionally, and preferably, as shown in more easily visible detail in FIG. 3, elastic adhesive substance gap filling surface layer 13 fills in depressions on the surface of rope 1 formed in between adjacent coverbraid strands 10. The core 2 is optional, and is preferred for deep sea deployment and retrieval applications, trawl warp applications and in the case of certain other applications, but not necessarily in the case of anchor lines and deep water oil derrick mooring and/or anchoring lines or yachting lines, although in some cases it may be used in such applications.

[0044] Shaped supportive core 3 also defines the first synthetic portion of the rope of the present disclosure mentioned above, and elastic adhesive substance layer 9 also defines the second synthetic portion of the rope of the present disclosure as mentioned above.

[0045] In order to form the rope of the present disclosure:

Preferred Fabrication Methods

[0046] There are two preferred embodiments of the present disclosure: one is a rope of the present disclosure for use in applications where the rope of the present disclosure is subject to storage under high compressive pressure, such as when used with high tension winches and drums, such as when used as a trawler's warp; another is where the rope of the present disclosure is not subject to storage under high compressive pressure, such as is common in many yachting applications.

[0047] In forming a preferred embodiment of the present disclosure for use in applications where the rope of the present disclosure is subject to storage under high compressive pressure:

[0048] First is provided a plurality of fibres and/or filaments formed of the second synthetic substance, that preferably is an Aramid, and preferably a new fibre known as T200WD. The fibres and/or filaments are used in forming several distinct primary strands 19. Preferably, twelve distinct primary strands 19 are formed. The primary strands 19 may be stranded directly from the fibres and/or filaments, or, first yarns may be formed and the yarns used to form the primary strands 19. The primary strands 19 may be braided, including loosely braided so as to provide noticeable constructional elongation, but twisted, and especially lightly twisted, as suitable for Aramids, and using known methods for forming strands formed of Aramids for use in forming a braided rope, is preferred.

[0049] Second, each of the distinct (the term “distinct” herein including “individual”) primary strands 19 is enclosed within a distinct sheath 21, known also herein as a “primary strand sheath”. Each distinct primary strand sheath 21 preferably is formed of a third synthetic substance having properties taught supra, and especially is formed of PTFE, but less preferably of HMPE or UHMWPE. The individual primary strand sheaths 21 may be formed by wrapping a tape formed of PTFE about each strand in such a fashion that edges of the tape overlap one another. The extent of the overlapping is such that after stretching steps taught herein the tape continues to cover all of the exterior of any distinct primary strand 19 about which the tape is used to form a distinct primary strand sheath 21. A fifty percent overlap is considered useful. However, it is presently preferred to form each of the distinct primary strand sheaths 21 as a braided sheath, where strands formed of PTFE may be used as strands to form each such braided primary strand sheath 21. Alternatively to PTFE, UHMWPE is also a suitable substance for the third synthetic substance, or tape like filaments of HMPE. When a braided sheath is selected for the individual primary sheaths 21, it is preferred to select to form the braided individual primary sheaths 21 with a braid angle that differs from the braid angle of any exterior sheath 8 that may be formed in subsequent steps as described herein and below. Most preferably, the braid angle selected for forming the braided individual primary sheaths 21 is a braid angle that is lesser than a braid angle selected for forming the exterior sheath 8, i.e. that is a “longer braid angle” or a “more acute” braid angle in comparison to a braid angle selected for forming the exterior sheath 8, the terms “longer braid angle” and “more acute braid angle” having the same meaning and being readily understood by those skilled in the art. The braid angle selected for the individual sheaths 21 may be similar (including “same”) as the twist angle selected for forming primary strands 19 from fibers. That is, the same angle defined by fibers and/or filaments, or by yarns, forming primary strands 19, relative to the long axis of a straight (not bent) primary strand 19, can be selected as the braid angle for forming the individual sheaths 21 when it is selected to form the individual sheaths 21 with a braided construction, and preferably with a hollow braided construction, as described in more detail below

[0050] Third, several, and preferably twelve of distinct primary strands 19 each enclosed within a distinct prima strand sheath 21.

[0051] Fourth, the primary strands 19 now enclosed within primary strand sheaths 21 are used to form a braided strength member having a hollow braided construction that is achieved by using a braiding machine to form the twelve (or other quantity) of primary strands 19 each enclosed within a distinct sheath 21 about a thermoplastic rod that forms the core 3, where the primary strands 19 are formed in a hollow braided construction about the thermoplastic rod forming the core 3. While twelve strands 19 are preferably preferred, it is possible to use from eight to forty-eight. Alternative to hollow braided, the strength member may be parallel laid, laid (including twisted) or plaited, but a hollow braided construction is preferred. It is highly preferably and important for a preferred embodiment of the instant disclosure that a hollow braided strength member is selected that has a thermoplastic core shaped so as to support the natural interior shape of the hollow braided strength member under tension approaching breaking strength of the strength member. Preferably, for a strength member is provided a braided strength member where the primary strands 19 forming the strength member have been stretched so as to remove constructional elongation and so as to cause compaction of the rope body, e.g. of the strength member and all contained within it, after the primary strands 19 have been braided into the strength member, so that the resultant strength member is unable to elongate greater than 5% before reaching break point when measured at an original tension of 1000 Kg, and preferably so that the resultant strength member is unable to elongate greater than 4% before reaching break point when measured at an original tension of 1000 Kg.

[0052] In forming a strength member for the preferred form of the instant disclosure the following further steps are employed:

[0053] First; a thermoplastic elongate object and especially a core formed of Polyethylene is provided, e.g. a PE rod, that ultimately forms core 3.

[0054] Second; a tightly woven braided flow-shield sheath 5 is braided around the thermoplastic rod. Filaments are selected to form the flow-shield sheath that are not made either liquid or semi-liquid at a temperature selected to change the phase of the thermoplastic rod, but rather that have a much higher softening point, and that are made of a synthetic substance unlike the synthetic substances of either the first, second, third or fourth synthetic substances, thus defining a fifth synthetic substance. Polyester is suitable.

[0055] Third; the primary strands 19 where each strand 19 is enclosed by a distinct primary strand sheath 21 are loaded onto bobbins that are loaded onto cars of a braided machine capable of forming hollow braids and are braided around the thermoplastic rod surrounded by a flow-shield sheath, so as to form a hollow braided strength member including a thermoplastic core surrounded by a flow-shield sheath.

[0056] Fourth; the braided strength member having the thermoplastic rod surrounded by the flow-shield sheath as its core is then subject to tension and to heat, preferably by being subject first to tension and secondly to heat, while maintaining the tension, in such a fashion and under such conditions that the thermoplastic selected to form the thermoplastic core becomes semi-liquid, i.e. molten, at a temperature that is used to permanently elongate the braided strength member by applying about thirteen percent of the cool strength member's breaking force to the heated strength member. The flow shield-sheath mainly or entirely stops the phase changed thermoplastic core from exiting the flow-shield sheath. That is, the majority of the thermoplastic core is unable to exit the flow-shield sheath even when the thermoplastic core is either liquid or semi-liquid, i.e. molten, despite enormous constrictive and compressive forces applied to the phase changed thermoplastic core as a result of the high tensions applied to the strength member, such high tensions able to permanently elongate the strength member under the conditions taught supra and herein.

[0057] A preferred tension to be used in the disclosed processes for forming the disclosed rope is about thirteen to fifteen percent (13-15%) of the break strength of the strength member when such break strength is measured at room temperature, with up to twenty-two percent being useful, and in some cases even more.

[0058] Importantly, the tension applied to the strength member, and thus necessarily also applied to the filaments forming the strength member, preferably is a static tension and/or a generally static tension and/or a very slowly fluctuating tension. After applying a predetermined tension (including approximately a predetermined tension), and while under such predetermined tension simultaneously the strength member, its filaments, and its thermoplastic core are heated to a predetermined temperature and/or to approximately a predetermined temperature as taught above and herein, with a minimum temperature of eighty (80) degrees C. being most preferred. The use of a long oven having many capstans able to accommodate a very long length of the strength member and turning at varying speeds and/or rates of rotation so as to maintain the tension on differing portions of the strength member located between different capstans, and thus by extension on the filaments forming the strength member as well as on the thermoplastic core also forming the strength member is highly useful, especially for permitting an endless flow production process.

[0059] Fifth; when the braided strength member and its thermoplastic core and the thermoplastic core's flow shield have been elongated to a predetermined amount so as to create an ultra-compact rope, and to experience a reduction in overall exterior diameter of the rope of thirty and up to forty-five percent in comparison to the rope's overall exterior diameter prior to the stretching and heat processing steps, the now elongated strength member and its elongated thermoplastic core are cooled while sufficient tension is maintained and applied to the strength member and thus by extension to its primary strands 19 and to its thermoplastic core 3 during the cooling process so that all such components are cooled to their respective solid states while under a tension that results in the cooled primary strands 19 as well as the cooled distinct primary strand sheaths 21 enclosing the primary strands 19, as well as the strength member and its thermoplastic core 3, having been permanently elongated so as to cause the strength member: [0060] a) to acquire a lower elongation than it had prior to its having been permanently elongated; [0061] b) to acquire a substantially lesser diameter and a greater compactness than it had prior to its having been permanently elongated; [0062] c) to acquire to its thermoplastic content core a permanent solid shape, having at its surface the flow shield sheath also taking the same shape as the exterior of the core, that supports the interior cavity of the permanently elongated hollow braided strength member in such a fashion that the filaments and braid strands forming the strength member are sufficiently less able to move relative to one another in a direction perpendicular to the long dimension of the permanently elongated strength member in comparison to prior to the strength member having been permanently elongated so as to reduce filament to filament abrasive wear, and also so as to preclude crushing of the rope, especially under high compressive forces such as occurs during winding and storage on a high tension drum, the necessary tension to achieve such result for any particular filament type able to be experimentally determined by one of ordinary skill in the art after having read the present disclosure.

[0063] This cooling also is best accomplished and undertaken using capstans turning at varying speeds so as to maintain a tension on the elongated strength member and its components during the entire cooling process and period that precludes their shortening, so that the final cooled strength member has the values of elongation to break point as taught above and herein for a most preferred embodiment of the instant disclosure, and also the other properties taught as above and herein, as also is accomplishable in an endless flow production method.

[0064] Sixth; optionally, and preferably, an elastic adhesive substance, that is a fourth synthetic substance, is used to adhere the formed strength member to an exterior braided sheath 8. The fourth synthetic substance is chosen as a flowable settable adhesive substance. While it is in a liquid and/or semi-liquid (including “flowable”) phase it is situated upon the outside surface of the preferably permanently elongated strength member, in contact with surfaces of multiple of the distinct primary strand sheaths 21 formed of the third synthetic substance. Then a preferably braided exterior sheath 8 is formed about the combination of the permanently elongated strength member and the flowable settable adhesive substance. The settable adhesive substance is situated upon the strength member at temperature that is lower than a phase change temperature of third synthetic substance. When a braided sheath is selected for the individual primary strand sheaths 21, it is preferred to select to form the braided individual primary strand sheaths 21 with a braid angle that differs from the braid angle of the exterior sheath 8. Most preferably, a braid angle selected for forming braided individual primary strand sheaths 21 is a braid angle that is lesser than a braid angle selected for forming the exterior sheath 8. The braid angle of the inner sheath 21 is an angle defined between (i) an imaginary line lying coaxial and parallel to the long axis of the primary strand 19 enclosed by the braided primary strand sheath 21 when the primary strand 19 is not curved or bent, but is straight; and (ii) a long dimension visible for any individual braid strand forming the braided construction of a primary strand sheath 21 when viewed in plan photographic view and when the primary strand 19 enclosed by the primary strand sheath 21 is straight (not bent). Similarly, the braid angle of the exterior sheath 8 is an angle defined between: (a) an imaginary line lying coaxial and parallel to the long axis of the rope when the rope is straight; and (b) a long dimension visible for any individual braid strand forming the braided construction of exterior sheath 8, when viewed in plan photographic view when the rope is straight.

[0065] Contrary to the state of the art, knowledge in the field and trend in the industry for forming braided sheaths, the braid angle selected for the individual sheaths 21 may, preferably, be similar (including “same”) as the twist angle selected for forming primary strands 19 from fibers. That is, the same angle defined by fibers and/or filaments, or by yarns, forming primary strands 19, relative to the long axis of an straight primary strand 19, can be selected as the braid angle for forming the individual sheaths 21 when it is selected to form the individual sheaths 21 with a braided construction, and preferably with a hollow braided construction.

[0066] When selecting to form at least one and preferably all of the individual primary strand sheaths 21 with a braided construction; this process step is further, and most preferably, modified by additionally selecting a braid tension for forming at least one, and preferably all, of the braided individual sheaths 21 that is a braid tension that is lesser than a braid tension selected for forming the exterior sheath 8 about the final formed and final processed strength member that preferably has had the elastic adhesive substance situated exterior the itself, i.e. situated exterior the final processed form of the strength member, prior to the exterior sheath 8 being braided about the strength member.

INDUSTRIAL APPLICABILITY

[0067] Ropes formed by teachings of the present disclosure may be used as crane ropes, deep sea deployment and recovery ropes, tow ropes, towing warps, trawl warps (also known as “trawlwarps”), deep sea lowering and lifting ropes, powered block rigged mooring ropes, powered block rigged oil derrick anchoring ropes used with blocks and also with powered blocks, deep sea mooring ropes, deep sea winch lines, superwides and paravane lines used in seismic surveillance including but not limited to being used with towed arrays, yachting ropes, rigging ropes for pleasure craft including but not limited to sail craft, running rigging, powered block rigged anchor ropes, drag lines, and other.

[0068] Although the present disclosure has been described in terms of the presently preferred embodiment, it is to be understood that such disclosure is purely illustrative and is not to be interpreted as limiting. Consequently, without departing from the spirit and scope of the disclosure, various alterations, modifications and/or alternative applications of the disclosure are, no doubt, able to be understood by those ordinarily skilled in the art upon having read the preceding disclosure. Accordingly, it is intended that the following claims be interpreted as encompassing all alterations, modifications or alternative applications as fall within the true spirit and scope of the disclosure.