DISINTEGRATING BINDERS FOR MULTI-MEMBER CABLE
20180358794 ยท 2018-12-13
Assignee
Inventors
Cpc classification
G02B6/4433
PHYSICS
G02B6/245
PHYSICS
H01B7/0241
ELECTRICITY
G02B6/4429
PHYSICS
G02B6/4431
PHYSICS
Y10T29/49117
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
H02G1/12
ELECTRICITY
G02B6/245
PHYSICS
Abstract
A multi-member cable includes at least a first cable element and a second cable element. The first and second cable elements may extend in parallel, be stranded in a helical winding pattern, or be stranded in a reverse-oscillatory winding pattern, along the length of the cable. At least one binder is helically wrapped about the first and second cable elements to hold them together. The binder is formed of a material which disintegrates when exposed to a particular liquid or heat. In a preferred embodiment, the binder may be formed of polyvinyl-alcohol (PVA).
Claims
1. A multi-member cable comprising: a first cable element; a second cable element, wherein said first and second cable elements abut each other; at least one binder helically wrapped about said first and second cable elements, so as to hold said first and second cable elements together, wherein said at least one binder is formed of a first material which disintegrates to lose at least 25% of its tensile strength within less than one minute when bought into contact with a liquid having a ph of between 4 and 10 and the liquid being at a temperature of between 32 to 212 degrees Fahrenheit; and an outer jacket formed over said first and second cable elements and said at least one binder.
2. The multi-member cable according to claim 1, wherein said first material disintegrates to lose at least 50% of its tensile strength within less than 30 seconds when bought into contact with the liquid having a ph of between 5 and 9 and the liquid being at a temperature of between 40 to 125 degrees Fahrenheit.
3. The multi-member cable according to claim 1, wherein said first material disintegrates to lose at least 80% of its tensile strength within less than 30 seconds when bought into contact with the liquid having a ph of between 6 and 8 and the liquid being at a temperature of between 40 to 125 degrees Fahrenheit.
4. The multi-member cable according to claim 1, wherein said first material disintegrates to a paste form, losing at least 90% of its tensile strength within less than one minute, when brought into contact with the liquid.
5. The multi-member cable according to claim 1, wherein said first material disintegrates to a paste form, losing at least 75% of its tensile strength within less than 30 seconds, when bought into contact with the liquid having a ph of between 5 and 9 and the liquid being at a temperature of between 32 to 212 degrees Fahrenheit.
6. The multi-member cable according to claim 1, wherein the liquid is water, such that said first material disintegrates when in contact with water.
7. The multi-member cable according to claim 1, wherein said first material is polyvinyl-alcohol.
8. The multi-member cable according to claim 1, wherein said first and second cable elements twist around a center axis of said multi-member cable three hundred sixty degrees in a first direction multiple times.
9. The multi-member cable according to claim 1, wherein said at least one binder is a first binder wrapping helically around said first and second cable elements in a clockwise direction, so as to hold said first and second cable elements together, wherein said first binder is formed of said first material, and further comprising: a second binder wrapping helically around said first and second cable elements in a counterclockwise direction, so as to hold said first and second cable elements together, wherein said second binder is formed of said first material, and wherein said outer jacket is formed over said first and second cable elements and said first and second binders.
10. The multi-member cable according to claim 9, wherein said first cable element is either a buffer tube with one or more optical fibers therein or an insulated conductor; and wherein said second cable element is either a buffer tube with one or more optical fibers therein or an insulated conductor, and further comprising: a third cable element; and a fourth cable element, wherein said first, second, third and fourth cable elements twist around a center axis of said multi-member cable three hundred sixty degrees in the counterclockwise direction multiple times to a first reversal point, then said first, second, third and fourth cable elements twist about the center axis of said multi-member cable three hundred sixty degrees in a clockwise direction multiple times until a second reversal point, and wherein said first, second, third and fourth cable elements repeat the pattern of counterclockwise and clockwise twists about the center axis of said multi-member cable between multiple first and second reversal points along the length of said multi-member cable.
11. The multi-member cable according to claim 10, further comprising: a central strength member approximately centered on the center axis of said multi-member cable.
12. A multi-member cable comprising: a first cable element; a second cable element, wherein said first and second cable elements abut each other; at least one binder helically wrapped about said first and second cable elements, so as to hold said first and second cable elements together, wherein said at least one binder is formed of a first material which disintegrates to permanently lose at least 25% of its tensile strength within less than one minute when heated to a temperature greater than 200 degrees Fahrenheit, but less than 600 degrees Fahrenheit; and an outer jacket formed over said first and second cable elements and said at least one binder.
13. The multi-member cable according to claim 12, wherein said first material disintegrates to permanently lose at least 50% of its tensile strength within less than 30 seconds when heated to a temperature greater than 300 degrees Fahrenheit, but less than 500 degrees Fahrenheit.
14. The multi-member cable according to claim 12, wherein said first material disintegrates to permanently lose at least 80% of its tensile strength within less than 30 seconds when heated to a temperature greater than 350 degrees Fahrenheit, but less than 470 degrees Fahrenheit.
15. The multi-member cable according to claim 12, wherein said first material disintegrates and undergoes pyrolysis, permanently losing at least 90% of its tensile strength within less than ten seconds, when heated to a temperature exceeding 350 degrees Fahrenheit, but not exceeding 470 degrees Fahrenheit.
16. The multi-member cable according to claim 12, wherein said at least one binder is a first binder wrapping helically around said first and second cable elements in a clockwise direction, so as to hold said first and second cable elements together, wherein said first binder is formed of said first material, and further comprising: a second binder wrapping helically around said first and second cable elements in a counterclockwise direction, so as to hold said first and second cable elements together, wherein said second binder is formed of said first material, and wherein said outer jacket is formed over said first and second cable elements and said first and second binders.
17. The multi-member cable according to claim 16, wherein said first cable element is either a buffer tube with one or more optical fibers therein or an insulated conductor; and wherein said second cable element is either a buffer tube with one or more optical fibers therein or an insulated conductor, and further comprising: a third cable element; a fourth cable element, wherein said first, second, third and fourth cable elements twist around a center axis of said multi-member cable three hundred sixty degrees in the counterclockwise direction multiple times to a first reversal point, then said first, second, third and fourth cable elements twist about the center axis of said multi-member cable three hundred sixty degrees in a clockwise direction multiple times until a second reversal point, and wherein said first, second, third and fourth cable elements repeat the pattern of counterclockwise and clockwise twists about the center axis of said multi-member cable between multiple first and second reversal points along the length of said multi-member cable; and a central strength member approximately centered on the center axis of said multi-member cable.
18. A method of performing a mid-span access of a multi-member cable comprising: removing a section of an outer jacket to expose first and second cable elements and at least one binder helically wrapped about the first and second cable elements; moistening the at least one binder until the binder disintegrates and releases the first and second cable elements; and splicing into at least one of the first and second cable elements.
19. The method according to claim 18, wherein moistening includes dampening a sheet of material and rubbing the sheet of material back and forth over the exposed at least one binder where the outer jacket has been removed.
20. The method according to claim 19, wherein the sheet of material is dampened with water.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limits of the present invention, and wherein:
[0024]
[0025]
[0026]
[0027]
[0028]
[0029]
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0030] The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
[0031] Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity. Broken lines illustrate optional features or operations unless specified otherwise.
[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.
[0033] As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms comprises and/or comprising, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term and/or includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as between X and Y and between about X and Y should be interpreted to include X and Y. As used herein, phrases such as between about X and Y mean between about X and about Y. As used herein, phrases such as from about X to Y mean from about X to about Y.
[0034] It will be understood that when an element is referred to as being on, attached to, connected to, coupled with, contacting, etc., another element, it can be directly on, attached to, connected to, coupled with or contacting the other element or intervening elements may also be present. In contrast, when an element is referred to as being, for example, directly on, directly attached to, directly connected to, directly coupled with or directly contacting another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed adjacent another feature may have portions that overlap or underlie the adjacent feature.
[0035] Spatially relative terms, such as under, below, lower, over, upper, lateral, left, right and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, elements described as under or beneath other elements or features would then be oriented over the other elements or features. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the descriptors of relative spatial relationships used herein interpreted accordingly.
[0036]
[0037] The third and sixth cable elements 55 and 58 are insulated conductors. For example, the third and sixth cable elements 55 and 58 may be 14 gauge conductors 63 surrounded by an insulation layer 65. The conductors 63 may be solid or stranded, and may be of smaller or larger sizes, e.g., 16 gauge, 12 gauge. The conductors 63 may be formed of copper, copper-clad-steel, aluminum or any other metal or alloy with good electrical conductivity. Although buffer tubes and insulated conductors are illustrated, the cable elements may also include other power and/or communication mediums, such as a coaxial power conductor, or a twisted pair within a buffer tube, or as an independent cable element. Further, one or more inexpensive filler rods may replace one or more of the power and/or communication mediums, when the intended deployment does not require all of the power and/or communication channels potentially offered by the multi-member cable 51. In practice, a filler rod has a same general diameter as the active cable elements, and assists in keeping the geometry of the multi-member cable 51 full for jacketing purposes.
[0038] In
[0039] The cable core 68 may also be configured with more or less cable elements, such as a five-around-one cable core (five cable elements around a central strength member 67), eight-around-one, ten-around-one or twelve-around-one. Also, the cable elements may have more than one orbit around the central strength member 67. For example, twelve-around-six-around-one (twelve cable elements around six cable elements around a central strength member 67) or fifteen-around-nine-around-one.
[0040] The outer diameter of the outer jacket 69 depends upon the cable core configuration and the size of the cable elements and the central strength member 67. Typical diameters range from 8 mm to 33 mm, such as 29 mm or 30 mm.
[0041] The multi-member cable 51 may optionally include additional elements like a water-blocking tape, water blocking gels inside and/or between the buffer tubes, rip cords, toning signal wires, drain/grounding wires, etc. The ripcords may be provided just beneath the outer jacket 69 and/or the armor layer 71.
[0042]
[0043] As best seen in
[0044] The number of turns between the first and second reversal points 27 and 29 depends upon the cable core configuration and dimension of the cable core elements and the central strength member 67. For example, five and a half turns to six turns might be feasible for the multi-member cable 51 of
[0045] Indications in the form of indicia may be printed or etched into the outer surface of the outer jacket 69. The indicia may be located at each first reversal point 27 along the length of the multi-member cable 51 or at each second reversal point 29 along the length of the multi-member cable 51. Preferably, the indicia are located at all of the first and second reversal points 27 and 29 along the length of the multi-member cable 51. The indicia may be printed/etched on the outer surface of the outer jacket 69 by the same manufacturing equipment which is already printing other indicia on the outer surface of the multi-member cable 51, like the manufacturer's identification, cable part number, manufacture date, length markers, etc.
[0046]
[0047] The cutting of the first and second binders 35A and 37A was rather time consuming and exposed the technician and cable elements to a risk of injury. Hence, the present invention has formulated the first and second binders 35A and 37A out of a new material, which does not need to be cut using a blade. The new material provides the first and second binders 35A and 37A with sufficient tensile strength to hold the cable core 68 together during the cable manufacturing process. Yet, the new material disintegrates to a tensile strength which can no longer hold the cable core together as the outer jacket 69 is extruded, or during the mid-span access procedure, as will be more fully explained below.
[0048] In a generic embodiment, the first and second binders 35A and 37A are formed of a first material which disintegrates to lose at least 25% of its tensile strength within less than one minute when bought into contact with a liquid having a ph of between 4 and 10 and the liquid being at a temperature of between 32 to 212 degrees Fahrenheit. In a more particular embodiment, the first material disintegrates to lose at least 50% of its tensile strength within less than 30 seconds when bought into contact with the liquid having a ph of between 5 and 9 and the liquid being at a temperature of between 40 to 125 degrees Fahrenheit. In an even more particular embodiment, the first material disintegrates to lose at least 75% to 80% of its tensile strength within less than 30 seconds when bought into contact with the liquid having a ph of between 5 and 9, such as between 6 and 8, and the liquid being at a temperature of between 32 to 212 degrees Fahrenheit, such as between 40 to 125 degrees Fahrenheit. In a preferred embodiment, the first material disintegrates to a paste form, losing at least 90% of its tensile strength within less than one minute, when brought into contact with the liquid, and the liquid is water (H.sub.2O).
[0049] One suitable material which meets such qualifications for the first material is known as polyvinyl-alcohol (PVA). PVA is a water-soluble synthetic polymer. It has the idealized formula of CH.sub.2CH(OH). It is used in papermaking, textiles, and a variety of coatings. Polyvinyl-alcohol is also known under the abbreviations PVOH and PVAl. Some forms of PVA have a density of 1.19 to 1.31 g/cm3. PVA is resistant to oil, grease and solvents. It has high tensile strength and flexibility. However, these properties are dependent on humidity, in other words, with higher humidity more water is absorbed by PVA. The water, which acts as a plasticiser, will then reduce its tensile strength.
[0050] One type of PVA thread is manufactured by the Madeira company (www.madeira.com). Of course, other sources of PVA threads, cords and films also exist. Further, PVA can be purchased in a raw material form, such as a bead or pellet form. Other materials which may be modified or substituted and exhibit similar characteristics to PVA may be included in the list of Poly(Ethenol), Ethenol, homopolymer, Polyviol, Vinol, Alvyl, Alcotex, Covol, Gelvatol, Lemol, Mowiol, Mowiflex, Alcotex, Elvanol, Gelvatol, Lemol, Mowiol, Nelfilcon A, Polyviol and Rhodoviol.
[0051]
[0052] A sheet of material, such as a paper towel or rag 101, is moistened or dampened with water, and the technician 103 rubs the rag 101 back and forth along the cable core 68. PVA rapidly disintegrates into a slim form having no, or almost no, tensile strength when brought into contact with water. Therefore, the first and second binders 35A and 37A become slimy and liquefy, since water acts as a plasticizer for PVA. The slimy PVA adheres to the rag 101, and hence, the first and second binders 35A and 37A are wiped clean from the cable core 68. This is a much quicker, easier and safer way to remove the first and second binders 35A and 37A, as compared to making multiple cuts using a bladed tool. The cable elements of the cable core 68 are released, freed from each other, and may be separated for a splicing operation, as shown in
[0053] PVA also rapidly disintegrates and changes its chemical composition, undergoing pyrolysis at high temperatures. For example, a mid-section of a cord of PVA will instantly break and the severed ends with shrink back and curl significantly when a high heat source, e.g., a flame passes by a section of the PVA cord for just a few milliseconds. In accordance with one source, PVA has a boiling point of about 445 degrees Fahrenheit (with fully hydrolysed PVA) and 356 to 374 degrees Fahrenheit (with partially hydrolysed grade PVA). PVA decomposes rapidly above 392 degrees Fahrenheit (fully hydrolysed PVA), as it undergoes pyrolysis, and decomposes rapidly at lower temperatures at lower hydrolysed levels.
[0054] In a generic embodiment, the first and second binders 35A and 37A are formed of a first material which disintegrates to permanently lose at least 25% of its tensile strength within less than one minute when heated to a temperature greater than 200 degrees Fahrenheit, but less than 600 degrees Fahrenheit. In a more particular embodiment, the first material disintegrates to permanently lose at least 50% of its tensile strength within less than 30 seconds when heated to a temperature greater than 300 degrees Fahrenheit, but less than 500 degrees Fahrenheit. In an even more particular embodiment, the first material disintegrates to permanently lose at least 80% of its tensile strength within less than 30 seconds when heated to a temperature greater than 350 degrees Fahrenheit, but less than 470 degrees Fahrenheit. In a preferred embodiment, the first material disintegrates and undergoes pyrolysis, permanently losing at least 90% of its tensile strength within less than ten second (such as less than one second), when heated to a temperature exceeding 350 degrees Fahrenheit, but not exceeding 470 degrees Fahrenheit.
[0055]
[0056] The technician 103 holds a heat source, e.g., a lighter 105, and runs the lighter 105 back and forth along the cable core 68, holding the flame 107 a distance from the cable core 68, like 3 to 4 inches. The distance and speed at which the flame 107 passes beneath the cable core 68 is sufficient to leave the elements 53, 54, 55, 56, 57 and 58 of the cable core 68 unharmed. However, PVA rapidly disintegrates and melts at a break line above the flame almost instantly. Therefore, the first and second binders 35A and 37A become disconnected above the path 109 of the flame 107, and short segments 111 of the first and second binders 35A and 37A are formed, which fall to the floor or can be wiped off of the cable core 68 with a rag or by hand. Hence, the cable elements 53, 54, 55, 56, 57 and 58 of the cable core 68 are released from the central strength member 67, freed from each other, and may be separated for a splicing operation, as shown in
[0057] Another use of the second property of PVA, would be to allow the extrusion temperature of the outer jacket 69 to partially or fully disintegrate the first and second binders 35A and 37A. The extrusion temperature of the outer jacket 69 is approximately 460 degrees Fahrenheit, in the case of an outer jacket formed of high density polyethylene (HDPE). In the case where no armor layer 71 is present, and the outer jacket 69 is extruded directly onto the first and second binders 35A and 37A of the cable core 68, the heat from the outer jacket 69 will most likely disintegrate fully, or at least partially, the majority of the tensile strength of the first and second binders 35A and 37A. It may also be possible to add a heat source to the manufacturing line (just upstream of or during the application of the armor layer 71 and/or the outer jacket 69) to fully or partially disintegrate the first and second binders 35A and 37A. Therefore, wherever the technician removes the outer jacket 69 along the cable 51, the underlying first and second binders 35A and 37A will be able to be wiped off with a dry rag or snapped off by hand with a rubbing action.
[0058] As best seen in
[0059] In accordance with the present invention, the technician no longer needs to cut off the binders 35 and 37 of the prior art. This saves time, and also reduces the risk of physical injury to the technician and damage to the cable elements 53, 54, 55, 56, 57 and 58 of the multi-member cable 51.
[0060] Although the cable core 68 has been illustrated with a reverse-oscillatory winding pattern, the benefits of the first and second binders 35A and 37A to hold cable cores with other configurations together during the manufacturing process will be appreciated by those of skill in the art. For example, the first and second binders 35A and 37A could be used to hold the cable core together where the cable core is helically stranded in only one direction over the entire length of the cable, or where the cable elements extend in parallel, i.e., are not stranded at all over the length of the cable.
[0061] Although the description has focused on removing the first and second binders 35A and 37A at a mid-span access, the first and second binders 35A and 37A of the present invention also allow for easy removal at end-of-cable terminations.
[0062] During the cable manufacturing process, the first and second binders 35A and 37A, of the present invention may be spooled onto reels, and used in a conventional cable manufacturing machine in the same manner as conventionally constructed first and second binders 35 and 37 (
[0063] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.