Composite rope structures and systems and methods for making composite rope structures

Abstract

A rope structure comprising a plurality of formed composite strands. Each of the formed composite strands comprises fiber material and matrix material. The fiber material within the matrix material is twisted. The shapes of the plurality of formed composite strands are predetermined to facilitate combination of the plurality of composite strands into the rope structure.

Description

RELATED APPLICATIONS

This application claims priority of U.S. Provisional Patent Application Ser. No. 60/930,853 filed May 18, 2007. This application also claims priority of U.S. Provisional Patent Application Ser. No. 60/931,088 filed May 19, 2007. The contents of all related applications listed above are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to composite rope structures and to systems and methods for making composite rope structures.

BACKGROUND

The need often exists for a rope structure to be arranged in tension between two objects. The characteristics of a given type of rope structure determine whether that type of rope structure is suitable for a specific intended use. Characteristics of rope structures include breaking strength, elongation, flexibility, weight, and surface characteristics such as abrasion resistance and coefficient of friction. Additionally, environmental factors such as heat, cold, moisture, exposure to UV light, abrasion, bending, and the like may affect the characteristics of a rope structure.

The intended use of a rope thus typically determines the acceptable range for each characteristic of the rope. The term “failure” as applied to rope will be used herein to refer to a rope being subjected to conditions beyond the acceptable range associated with at least one rope characteristic.

The need thus exists for rope structures having improved rope characteristics for specific environments; the need also exists for systems and methods for producing such ropes.

SUMMARY OF THE INVENTION

The present invention may be embodied as a rope structure comprising a plurality of formed composite strands. Each of the formed composite strands comprises fiber material and matrix material. The fiber material within the matrix material is twisted. The shapes of the plurality of formed composite strands are predetermined to facilitate combination of the plurality of composite strands into the rope structure.

The present invention may also be embodied as a method of forming a rope structure, comprising the following steps. Fiber material is arranged within matrix material to obtain blank material. The fiber material within the matrix material of the blank material is twisted to obtain unformed composite strands. The plurality of unformed composite strands are worked to obtain formed composite strands, where each of the formed composite strands has a predetermined shape. The formed composite strands are combined into the rope structure.

The present invention may also be embodied as a rope structure comprising a plurality of formed composite strands. The formed composite strands comprise fiber material and matrix material. The fiber material within the matrix material is twisted. At least one of the formed composite strands is substantially cylindrical. A plurality of the formed composite strands are substantially helical. The substantially helical formed composite strands are formed around the at least one substantially cylindrical formed composite strand to obtain the rope structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts a plurality of formed composite strands assembled around a core strand to form a composite rope structure;

FIG. 1B is a cross-section of the composite rope structure depicted in FIG. 1A;

FIG. 2 is a somewhat schematic view of a blank forming system for performing the step of forming a composite blank used as part of the systems and methods of the present invention;

FIG. 3 is a section view depicting the composite blank created by the system depicted in FIG. 2;

FIG. 4 is a somewhat schematic view of a blank twisting system for performing the step of converting the composite blank created by the system depicted in FIG. 2 into an unformed composite strand;

FIGS. 5 and 6 are somewhat schematic views of a system for performing the step of converting the unformed composite strand created by the system of FIG. 4 into a formed composite strand;

FIG. 7 depicts an example of a formed composite strand created by the system of FIGS. 5 and 6;

FIG. 8 is a somewhat schematic view of another example blank forming system for performing the steps of forming a composite blank and converting the composite blank into a linear composite strand; and

FIG. 9 is a cross-section of an example composite rope structure manufactured using strands formed by the blank forming system depicted in FIG. 8.

FIG. 10 is a highly schematic view of a twisting system that may be used by a second example process of fabricating a composite rope structure according to the principles of the present invention;

FIG. 11 is a highly schematic view of a first combination system that may be used by the second example fabrication process;

FIG. 12 is a highly schematic view of a second combination system that may be used by the second example fabrication process;

FIG. 13 is a cross-section of an example yarn that may be used by a composite rope structure of the present invention;

FIG. 14 is a cross-section of an example strand that may be used by a composite rope structure of the present invention;

FIG. 15 is a cross-section of another example that may be used by a composite rope structure of the present invention;

FIG. 16 is a cross-section of an example composite rope structure of the present invention; and

FIG. 17 is a cross-section of another example composite rope structure of the present invention.

DETAILED DESCRIPTION

Referring initially to FIGS. 1A and 1B of the drawing, depicted therein is a composite rope structure 20 constructed in accordance with, and embodying, the principles of the present invention. The composite rope structure 20 comprises a plurality of formed composite strands 22 and a core strand 24. As perhaps best shown in FIG. 7, the formed composite strands 22 are preformed in a substantially helical configuration such that a plurality (two or more) of these formed composite strands 22 are combined with the core strand 24 to form the composite rope structure 20. The example composite rope structure 20 comprises six composite strands 22 surrounding a single core strand 24.

The composition and fabrication of the example formed composite strands 22 will now be described in further detail. Depicted in FIG. 2 of the drawing is an example blank forming system 30. The blank forming system 30 comprises a plurality of feed rollers 32, with each feed roller 32 containing a length of fiber 34. For clarity, the example blank forming system 30 illustrates five feed rollers 32 and five fibers 34. While it is possible that five or fewer fibers can be used as shown, typically more than five fibers will be used.

The fibers 34 are flexible and thus can be unrolled from the feed rollers 32 and combined into a bundle 36. The example bundle 36 of fibers 34 simply comprises a group of parallel fibers. As will be described in further detail below, the bundle may be formed by twisting, braiding, or otherwise mechanically intertwining the fibers as the bundle is formed.

The bundle 36 of fibers 34 is fed through a matrix bath 40 and a shaping die 42 to obtain uncured composite blank material 44. As shown in FIG. 3, the matrix bath 40 contains matrix material that forms a matrix 46 around and between the fibers 34. At this point, the matrix material is sufficiently fluid to flow between and around the fibers 34 but is sufficiently plastic to hold its shape after passing through the shaping die 42. The matrix bath 40 may be pressurized to facilitate flow of the matrix material between and around the fibers 34.

FIG. 3 further shows that the example shaping die 42 forms the uncured composite blank material 44 in a substantially cylindrical shape. The die 42 may, however, be configured to form the matrix 46 into other shapes. For example, the die 42 may be configured to form the matrix 46 into a shape engineered to obtain desired characteristics of the completed composite rope structure 20 as will be described in further detail below.

Referring back to FIG. 2 of the drawing, the uncured composite blank material 44 is processed in a dryer 50 to obtain processed composite blank material 52. The processed composite blank material may be cured, partly cured, or uncured. At this point, the processed matrix material can be in a plastic or flexible form or may be transformed from a plastic form into a rigid form. The example matrix 46 thus is solidified around the fibers 34 such that the processed composite blank material 52 holds its substantially cylindrical form and is substantially straight.

The example processed composite blank material 52 is then fed into a cutter 60, which cuts the processed composite blank material 52 into composite blanks 62 comprising the matrix 46 and fibers 34. The example composite blanks 62 are rigid, elongate bodies that are substantially cylindrical, substantially straight or linear, and have a length predetermined by the parameters of the cutter 60. However, if partly cured or uncured, the composite blank material 52 may be flexible or semi-rigid, in which case the processed composite blank material need not be cut into blanks 62 using the cutter 60. Instead, the composite blank material 52 may be wound onto a bobbin or the like for storage and/or further processing as will be described below.

Another example composite rope structure may comprise composite strands 22 formed by commingled yarns. Commingled yarns consist of combination of at least two types of high-performance yarns such as carbon yarn and matrix-forming thermoplastic yarns such as polyethylene yarns. Under heat, the matrix-forming yarns with the lower melting temperature melt and form the matrix for the high-performance yarns. Following the similar process as the impregnated yarns described above, the commingled yarns pass through a heat chamber and a shaping die. When cooled, the composite stand 22 is formed.

Referring now to FIG. 4 of the drawing, depicted therein is a blank twisting system 70 for converting the example composite blanks 62 into unformed composite strands 72. The blank twisting system 70 comprises an anchor assembly 74, a twist assembly 76, and a heating assembly 78. In particular, the composite blanks 62 are connected between the anchor assembly 74 and twist assembly 76, and the composite blanks 62 are heated along substantially the entire length thereof using the heating assembly 78.

The heat applied by the heating assembly 78 renders the matrix material of the composite blanks 62 back into plastic form. The anchor assembly 74 holds one end of the composite blank 62, while the twist assembly 76 twists the composite blank 62 about a longitudinal axis thereof. Because the matrix material is plastic, the matrix 46 deforms as the composite blank 62 is heated to allow the fibers 34 within the composite blank 62 to twist. When a desired amount of twist has been applied to the composite blank 62, the matrix material is allowed to cool such that the matrix 46 solidifies in a new form around the twisted fibers 34 to obtain an unformed composite strand 72 (FIG. 5). If the composite blank material 52 is collected on a bobbin or the like and not cut into the example composite blanks 62, the bobbin itself may be rotated to twist the composite blank material 52 about the axis thereof.

From the outside, only the matrix 46 is visible; the unformed composite strand 72 is a rigid, elongate body that is substantially cylindrical, substantially straight or linear, and has a length predetermined by the parameters of the cutter 60; the unformed composite strand 72 thus looks very much like the composite blank 62. However, where the fibers 34 are arranged within the composite blank 62 in a substantially parallel manner, the fibers 34 within the unformed composite strand 72 are internally twisted.

Referring now to FIGS. 5 and 6 of the drawing, depicted therein is a forming system 80 that converts the unformed composite strands 72 into the formed composite strands 22 (FIG. 7). The forming system 80 comprises a guide assembly 82, a feed assembly 84, and a twist assembly 86. The guide assembly 82 comprises guide member 90, a guide bearing 92, and a guide clamp 94. The feed assembly 84 comprises a heater assembly 96 and a feed sleeve 98.

The guide member 90 is an elongate, rigid member having a shape and length similar to those of the core member 24. One end of the guide member 90 is rotatably supported by the guide bearing 92, and the other end of the guide member 90 is supported by the twist assembly 86. The feed assembly 84 is held in a predetermined relationship with the guide bearing 92.

As shown in FIG. 5, the unformed composite strand 72 is secured to the guide member 90 by guide clamp 94. The unformed composite strand 72 is then heated by the heater assembly 96 such that the matrix material is again rendered plastic. The twist assembly 86 is then rotated as shown by arrow A about a guide axis defined by the longitudinal axis of the guide member 90 and drawn away from the guide bearing 92 along the guide axis as show by arrow B.

As the twist assembly 86 rotates about and moves along the guide axis, the unformed composite strand 72 is pulled through the heater assembly 96 and the feed sleeve 98 and wrapped around the guide member 90. In addition, as the portion of the unformed composite strand 72 wrapped around the guide member 90 moves away from the heater assembly of the feed assembly 84, the matrix material cools and again becomes substantially rigid.

The twisting and pulling of the unformed composite strand 72 continues until the entire strand 72 has been pulled through the feed assembly 84 and wrapped around the guide member 90. After the entire unformed composite strand 72 has been wrapped around the guide member 90 and the matrix material allowed to cool, the unformed composite strand 72 has been transformed into the formed composite strand 22. The formed composite strand 22 is then removed from the guide member 90.

The example formed composite strand 22 is generally circular in cross-section at any point along its length but takes a substantially helical form determined by the diameter of the guide member 90, the rotational speed at which the twist assembly 86 rotates about the guide axis, and the displacement speed at which the twist assembly 86 is displaced along the guide axis. The helical configuration of the formed composite strand 22 can thus be quantified using the parameters of inner diameter D determined by the diameter of the guide member 90 and pitch P determined by the rotational speed and displacement speed of the twist assembly 86.

The helical configuration of the formed composite strand 22 is predetermined such that a plurality of the composite strands 22 can be combined with the core 24, as shown in FIGS. 1A and 1B to obtain the composite rope structure 20. In particular, in a situation in which six formed composite strands 22 are wrapped around the core 24, the inner diameter D is substantially the same as the diameter of the core 24, and the pitch P is sufficient to allow the six strands 22 to wrap around the core 24 with substantially no space between the strands 22. The geometry of the formed composite strand 22 will thus vary with different cores and different numbers of strands.

The matrix material used to form the example formed composite strands 22 is thermoplastic polyurethane system, and the fibers 34 are glass fibers. However, other thermoplastic resin systems materials such as polyesters, polyethylene, polypropylene, nylon, PVC, and their mixtures may be used to form the matrix. In addition, high performance fibers such as carbon fibers, aramid fibers, polyester fibers, PBO, PBI, basalt, Vectran, HMPE, and ceramic fibers may be used.

Referring now for a moment to FIG. 8 of the drawing, depicted therein is another example blank forming system 120 that may be used to replace the blank forming system 30 and blank twisting system 70 described above.

The example blank forming system 120 combines the functions of both the blank forming system 30 and the blank twisting system 70 to generate a composite rope structure 122 as represented in FIG. 9 of the drawing.

In particular, the blank forming system 120 creates unformed composite strands 124 that are compositionally similar to the unformed composite strands 72 described above. Although the geometry of the unformed composite strands 124 may also be the same as the geometry of the unformed composite strands 72, the example unformed composite strands 124 have a different geometry, as will be described further below.

The unformed composite strands 124 are converted into formed composite strands 126, and the formed composite strands 126 are combined with a core 128 to form the composite rope structure 122.

Referring now back to FIG. 8, the blank forming system 120 comprises a plurality of feed rollers 130, with each feed roller 130 containing a length of fiber 132. For clarity, the example blank forming system 120 illustrates five feed rollers 130 and five fibers 132. Again, while it is possible that five or fewer fibers can be used as shown, more than five fibers will typically be used when making the formed composite strands 126.

The fibers 132 are flexible and thus can be unrolled from the feed rollers 130 and combined into a twisted bundle 134 using a combining assembly 136. The combining assembly 136 intertwines the fibers 132 such that the fibers 132 in the twisted bundle 134 are twisted. The twisted bundle 134 may also be formed by braiding or otherwise mechanically intertwining the fibers.

The twisted bundle 134 of fibers 132 is fed through a matrix bath 140 and a shaping die 142 to obtain an uncured composite blank material 144. The matrix bath 140 contains matrix material that forms a matrix around and between the fibers 132. At this point, the matrix material is sufficiently fluid to flow between and around the fibers 132 forming the twisted bundle 134 but is sufficiently plastic to hold its shape after passing through the shaping die 142.

The example shaping die 142 forms the uncured composite blank material 144 in a substantially trapezoidal shape in cross-section. As will become apparent from the following discussion, the example die 142 is thus configured to form the matrix into a shape engineered to obtain desired characteristics of the completed composite rope structure 122.

Referring back to FIG. 8 of the drawing, the uncured composite blank material 144 is cured in a dryer 150 to obtain preformed composite blank material 152. At this point, the matrix material may be cured and thus transformed from a plastic form into a rigid form; alternatively, the matrix material may be uncured or only partly cured, in which case the composite blank material 144 is still plastic or flexible. The example matrix is sufficiently solidified around the fibers 132 that the preformed composite blank material 152 holds its substantially trapezoidal form and is substantially straight.

The cured composite blank material 152 is then fed into a cutter 160, which cuts the cured composite blank material 152 into the unformed composite strands 124. The example composite strands 124 are thus rigid, elongate bodies that are substantially straight or linear and have a length predetermined by the parameters of the cutter 160.

Again, only the matrix 146 is visible from the outside; the unformed composite strand 124 is a rigid, elongate body that is substantially straight or linear, and has a length predetermined by the parameters of the cutter 160. In addition, because the fibers 132 were twisted by the twisting assembly 136, the fibers 132 within the unformed composite strands 124 are twisted. The unformed composite strands 124 are then processed using a forming system such as the example forming system 80 described above to obtain the formed composite fibers 126.

The formed composite fibers 126 are then wrapped around the core 128 to form the composite rope structure 122. As described above, the unformed composite strands 124 have a generally trapezoidal cross-section. This geometry allows the strands to be wrapped around the core 128 with little or no space between any parts of the adjacent formed composite strands 126. The inner surfaces of the formed composite strands engage the core 128 with little or no space between the formed composite strands 126 and the core 128. In addition, the outer surfaces of the formed composite strands 126 are configured such that rope structure 122 has substantially cylindrical outer surface.

Referring now to FIGS. 10, 11, and 12 of the drawing, depicted therein is system and method for forming another example composite rope in accordance with, and embodying, the principles of the present invention.

Referring initially to FIG. 10, depicted therein is a twisting system 220 for twisting impregnated yarns 222; the impregnated yarns 222 are identified in their untwisted state by reference character 222a and in their twisted state by reference character 222b.

The impregnated yarns 222 are composite structures comprising fibers and resin. The fibers are primarily responsible for the strength properties of the yarns 222 under tension loads. The resin forms a matrix of material that surrounds the fibers and transfers loads between the fibers. The resin matrix further protects the fibers from the surrounding environment. As examples, the resin matrix can be formulated to protect the fibers from heat, UV light, abrasion, and other external environmental factors.

The example resin portion of the impregnated yarns 222 exists in an uncured state and a cured state. In the uncured state, the resin material is flexible, and the matrix allows the impregnated yarns 222 to be bent, twisted, and the like. In general, the resin matrix becomes more plastic or malleable when heated, up to a cure temperature. Above the cure temperature, the resin matrix cures and becomes substantially more rigid. The properties of the resin matrix can be adjusted for manufacturing convenience and/or for a particular intended operating environment of the final composite rope structure.

The example impregnated yarns 222 comprise approximately 90% by weight of fibers and approximately 10% by weight of resin. The fibers may be in a first range of substantially between 85% and 95% by weight of the yarn but in any event should be within a second range of substantially between 70% and 98% by weight of the yarn. The resin may be in a first range of substantially between 5% and 15% by weight of the yarn but in any event should be within a second range of substantially between 2% and 30% by weight of the yarn.

An alternative example of the impregnated yarns 222 may comprise approximately 80% by weight of fibers and approximately 20% by weight of resin. The fibers may be in a first range of substantially between 75% and 90% by weight of the yarn but in any event should be within a second range of substantially between 50% and 95% by weight of the yarn. The resin may be in a first range of substantially between 10% and 25% by weight of the yarn but in any event should be within a second range of substantially between 5% and 50% by weight of the yarn.

The example fibers are glass fibers but may be one or a combination of carbon fibers, aramid fibers, polyester fibers, PBO, PBI, basalt, HMPE, and ceramic fibers. The resin is a thermoplastic polyurethane, but other thermoplastic materials such as polyester, polyethylene, polypropylene, nylon, PVC, plastisols, and their mixtures may also be used.

The example twisting system 220 comprises a first bobbin 224a for storing the untwisted impregnated yarns 222a and a second bobbin 224b for storing the twisted impregnated yarns 222b. The untwisted impregnated yarn 222a is unwound from the first bobbin 224a, twisted, and taken up on the second bobbin 224b as the twisted impregnated yarn 222b.

In the example twisting system 220, the second bobbin 224b rotates about a primary axis of rotation A and also rotates about a twist axis of rotation B defined by the impregnated yarn 222. The rotation of the second bobbin 224b about the primary axis A and the twist axis B converts the untwisted impregnated yarn 222a into the twisted impregnated yarn 222b and winds the twisted impregnated yarn 222b on the second bobbin 224b. Where the fibers forming the untwisted impregnated yarn 222a are substantially straight and parallel, the fibers forming the twisted impregnated yarn 222b take on a generally helical configuration.

The untwisted impregnated yarn 222a may be twisted at room temperature. However, to facilitate the twisting process, the twisting system 220 further optionally comprises a heating stage 226 for heating the untwisted impregnated yarns 222a before, as, and/or after they are twisted. The heating stage 226 increases the temperature of the resin matrix of the untwisted impregnated yarns 222a to a temperature that is elevated but below the cure temperature of the resin matrix.

By softening the resin forming the matrix portion of the untwisted impregnated yarns 222a, the fibers can more easily be twisted into the substantially helical configuration. Also, when preheated prior to, as, and/or after they are twisted and then allowed to cool, the resin matrix portion of the twisted impregnated yarns 222b is more likely to maintain the fibers in the substantially helical configuration.

The example twisting system 220 further optionally comprises a release agent stage 228 for applying a release agent to the twisted impregnated yarns 222b as they are taken up on the second bobbin 224b. The release agent or similar chemicals help to prevent the binding among the twisted impregnated yarns at the elevated temperature or when curing in the subsequent combination of the twisted impregnated yarns 222b with other rope components as will be described below.

FIG. 11 illustrates a first example combining system 230 for combining multiple uncured twisted impregnated yarns 222b into a strand 232. The example strand 232 comprises seven twisted impregnated yarns 222b in what will be referred to as a 1×7 configuration. The twisted impregnated yarns 222b may, however, be combined using fewer or more yarns and in combination structures other than a 1×7 configuration.

To form the example strand 232, seven of the second bobbins 224b are supported by a first rotator assembly 234. The first rotator assembly 234 is or may be conventional and will be described herein only as necessary for a complete understanding of the present invention. The example first rotator assembly 234 comprises a central bobbin mount 236 and a six perimeter bobbin mounts 238. The central bobbin mount 236 allows the second bobbin 224b supported thereon to rotate about its primary axis A. The second bobbins 224b are supported by the perimeter bobbin mounts 238 for rotation about their primary axes A.

The perimeter bobbin mounts 238 further support the second bobbins 224b for rotation together about a system axis C defined by the first rotator assembly 234. The central bobbin mount 236 may be supported with the perimeter bobbin mounts 238 such that the second bobbin 224b supported thereby also rotates about the system axis C with the second bobbins 224b supported at the perimeter bobbin mounts 238. Alternatively, the central bobbin mount 236 may be supported independent of the perimeter bobbin mounts 238 such that the second bobbin 224b supported thereby rotates only about its primary axis A and not about the system axis C.

As the twisted impregnated yarns 222b are withdrawn from the first rotator assembly 234, the twisted impregnated yarns 222b unwound from the second bobbins 224b at the perimeter bobbin mounts 238 are combined with the twisted impregnated yarn 222b unwound from the second bobbin mount 224b at the central bobbin mount 236 to form the strand 232. In the example system 230, the strand 232 is taken up on a strand bobbin 240.

The twisted yarn 222b unwound from the second bobbin mount 224b at the central bobbin mount 236 forms a core impregnated yarn of the strand 232. The fibers in the core impregnated yarn maintain the substantially helical configuration created by the twisting system 220. The twisted impregnated yarns 222b around core yarn will be referred to as the perimeter yarns. The fibers in the perimeter yarns maintain the substantially helical configuration created by the twisting system 220 but will also have a secondary helical configuration centered about the core yarn. The fibers in the perimeter yarns thus have a substantially double helical configuration.

The twisted impregnated yarns 222b may be combined to form the strand 232 at room temperature. However, to facilitate the combination process, the first combination system 230 further optionally comprises a heating stage 242 for heating the twisted impregnated yarns 222a before and/or as they are combined. The heating stage 242 increases the temperature of the resin matrix of the twisted impregnated yarns 222b to a temperature that is elevated but below the cure temperature of the resin matrix.

By softening the resin forming the matrix portion of the twisted impregnated yarns 222b the twisted impregnated yarns 222b can more easily be combined into the strands 232 with fibers of the core yarns in the substantially helical configuration and the fibers in perimeter yarns in the substantially double helical configuration. Also, when preheated prior to, as, and/or after they are twisted and then allowed to cool, the resin matrix portion of the twisted impregnated yarns 222b is more likely to maintain the fibers of the core impregnated yarn in the helical configuration and the fibers in the perimeter impregnated yarns in the substantially double helical configuration.

The example combination system 230 further optionally comprises a release agent stage 244 for applying a release agent to each of the strands 232 as they are taken up on the strand bobbin 240. The release agent or similar chemicals help to prevent the binding among the strands 232 at the elevated temperature or when curing in the subsequent combination of the strand 232 with other rope components as will be described below.

The example second combination system 230 further comprises an optional shaping die 246. The shaping die 246 is arranged where the ends are twisted and joined together.

The example strand 232 may be cured by heating the strand 232 above the cure temperature to form a first example composite rope structure. In particular, when cured, the characteristics of the strand 232 may satisfy the requirements of the intended operating environment. Other operating environments may require that a plurality of the strands 232 to be combined to form the final composite rope structure. In this case, the resin matrix of the strands 232 will be left uncured or only partly cured.

FIG. 12 illustrates a second combining system 250 for combining multiple strands 232 into a rope structure 252. The example rope structure 252 comprises seven strands 232 in what will be referred to as a 7×7 configuration. The strands 232 may, however, be combined using fewer or more yarns and/or strands and in combination structures other than a 7×7 configuration.

To form the example rope structure 252, seven of the strand bobbins 240 are supported by a second rotator assembly 254. The second rotator assembly 254 is or may be conventional and will be described herein only as necessary for a complete understanding of the present invention. The example second rotator assembly 254 comprises a central bobbin mount 256 and a six perimeter bobbin mounts 258. The central bobbin mount 256 allows the strand bobbin 240 supported thereon to rotate about its primary axis. The strand bobbins 240 supported by the perimeter bobbin mounts 258 are supported for rotation about their primary axes.

The perimeter bobbin mounts 258 further support the strand bobbins 240 for rotation together about a system axis D defined by the second rotator assembly 254. The central bobbin mount 256 may be supported with the perimeter bobbin mounts 258 such that the strand bobbin 240 supported thereby also rotates about the system axis D with the strand bobbins 240 supported at the perimeter bobbin mounts 258. Alternatively, the central bobbin mount 256 may be supported independent of the perimeter bobbin mounts 258 such that the strand bobbin 240 supported thereby rotates only about its primary axis A and not about the system axis D.

As the strands 232 are withdrawn from the second rotator assembly 254, the strands 232 unwound from the strand bobbins 240 at the perimeter bobbin mounts 258 are combined with the strand 232 unwound from the strand bobbin 240 at the central bobbin mount 256 to form the rope structure 252. In the example system 250, the rope structure 252 is taken up on a rope bobbin 260.

The strand 232 unwound from the strand bobbin 240 at the central bobbin mount 256 forms a core strand of the rope structure 252. The fibers in the core strand maintain the shape created by the first combination system 230. The strands 232 around core strand will be referred to as the perimeter strands. The fibers in the perimeter yarns of the perimeter strands maintain the shape created by the first combining system 230 but will also have a tertiary helical configuration centered about the core strand. The fibers in the perimeter yarns thus have a substantially-triple helical configuration.

The strands 232 may be combined to form the rope structure 252 at room temperature. However, to facilitate the combination process, the second combination system 250 further optionally comprises a heating stage 262 for heating the strands 232 before, as and/or after they are combined. The heating stage 262 increases the temperature of the resin matrix of the strands 232 to a temperature that is elevated but below the cure or melting temperature of the resin system.

By softening the resin forming the matrix portion of the strands 232, the strands 232 can more easily be combined into the strands 232 with fibers of maintaining the appropriate helical configurations. Also, when preheated prior to, as, and/or after they are twisted and then allowed to cool, the resin matrix portion of the strands 232 is more likely to maintain the fibers in the appropriate helical configurations.

The example second combination system 250 further comprises an optional shaping die 264. The shaping die 264 is arranged where the ends are twisted and joined together.

Turning now to FIGS. 13-17 of the drawing, depicted therein are somewhat schematic representations of the cross-sections of impregnated yarns, strands, and rope structures that may be fabricated using the principles of the present invention. FIG. 13 represents the cross-section of one of the twisted impregnated yarns 222b. FIG. 14 represents the cross-section of the example strand 232 described above comprising seven of the twisted impregnated yarns 222b (1×7 configuration). FIG. 15 represents the cross-section of another example strand 270 that may be formed by combining nineteen of the twisted yarns 222b (1×19 configuration). FIG. 16 represents the cross-section of the example rope structure 252 described above comprising seven of the example strands 232 (7×7 configuration). FIG. 17 represents the cross-section of another example rope structure obtain by combining seven of the example strands 270 described above (7×19 configuration).

Given the foregoing, it should be apparent that the present invention may be embodied in forms other than those described above. The scope of the present invention should be determined with reference to the claims appended hereto and not the foregoing detailed description of examples of the present invention.

Claims

1. A rope structure comprising:

a plurality of formed composite strands comprising fiber material and matrix material; wherein

the fiber material within the matrix material is twisted; and

the shapes of the plurality of formed composite strands are predetermined to facilitate combination of the plurality of composite strands into the rope structure.

2. A rope structure as recited in claim 1, in which the formed composite strands are substantially helical.

3. A rope structure as recited in claim 1, in which the shapes of the formed composite strands are predetermined based on geometry of the rope structure.

4. A rope structure as recited in claim 1, in which the matrix material of the formed composite strands is cured.

5. A rope structure as recited in claim 1, in which the fiber material is made from at least one fiber selected from the group consisting of carbon fibers, aramid fibers, polyester fibers, PBO, PBI, basalt, HMPE, and ceramic fibers.

6. A rope structure as recited in claim 1, in which the matrix material is at least one material selected from the group of materials consisting of thermoplastic polyurethane, polyester, polyethylene, polypropylene, PVC, and nylon.

7. A rope structure as recited in claim 1, in which:

the fiber material is at least one fiber selected from the group of fibers consisting of carbon fibers, aramid fibers, polyester fibers, PBO, PBI, basalt, HMPE, and ceramic fibers; and

the matrix material is at least one material selected from the group of materials consisting of thermoplastic polyurethane, polyester, polyethylene, polypropylene, PVC, and nylon.

8. A rope structure as recited in claim 1, in which the formed composite strands comprise a plurality of yarns.

9. A rope structure as recited in claim 8, in which the formed composite strands comprise substantially between 70% and 98% by weight of the fiber material.

10. A rope structure as recited in claim 8, in which the formed composite strands comprise substantially between 2% and 30% by weight of the matrix material.

11. A rope structure as recited in claim 8, in which the formed composite strands comprise:

substantially between 70% and 98% by weight of the fiber material; and

substantially between 2% and 30% by weight of the matrix material.

12. A rope structure as recited in claim 8, in which the formed composite strands comprise substantially between 50% and 95% by weight of the fiber material.

13. A rope structure as recited in claim 8, in which the formed composite strands comprise substantially between 5% and 50% by weight of the matrix material.

14. A rope structure as recited in claim 8, in which the formed composite strands comprise:

substantially between 50% and 95% by weight of the fiber material; and

substantially between 5% and 50% by weight of the matrix material.

15. A method of forming a rope structure, comprising the steps of:

providing fiber material;

providing matrix material;

arranging the fiber material within the matrix material to obtain blank material;

twisting the fiber material within the matrix material of the blank material to obtain unformed composite strands; and

working the plurality of unformed composite strands to obtain formed composite strands, where each of the formed composite strands has a predetermined shape; and

combining the formed composite strands into the rope structure.

16. A method as recited in claim 15, in which the step of working the plurality of the formed composite strands comprises the step of heating the unformed composite strands.

17. A method as recited in claim 15, further comprising the step of predetermining the shapes of the formed composite strands based on geometry of the rope structure.

18. A method as recited in claim 15, further comprising the step of curing the matrix material of the formed composite strands.

19. A method as recited in claim 15, further comprising the steps of:

selecting the fiber material from the group consisting of carbon fibers, aramid fibers, polyester fibers, PBO, PBI, basalt, HMPE, and ceramic fibers; and

selecting the matrix material from the group of materials consisting of polyurethane, polyester, polyethylene, polypropylene, PVC and nylon.

20. A rope structure comprising:

a plurality of formed composite strands comprising fiber material and matrix material; wherein

the fiber material within the matrix material is twisted; and

at least one of the formed composite strands is substantially cylindrical;

a plurality of the formed composite strands are substantially helical; and

the substantially helical formed composite strands are formed around the at least one substantially cylindrical formed composite strand to obtain the rope structure.

21. A rope structure as recited in claim 20, in which the matrix material of the formed composite strands is cured.

22. A rope structure as recited in claim 20, in which:

the fiber material is at least one fiber selected from the group of fibers consisting of carbon fibers, aramid fibers, polyester fibers, PBO, PBI, basalt, HMPE, and ceramic fibers; and

the matrix material is at least one material selected from the group of materials consisting of thermoplastic polyurethane, polyester, polyethylene, polypropylene, PVC, and nylon.

23. A rope structure as recited in claim 20, in which:

the formed composite strands comprises substantially between 70% and 98% by weight of the fiber material; and

the formed composite strands comprise substantially between 2% and 30% by weight of the matrix material.

24. A rope structure as recited in claim 20, in which:

the formed composite strands comprises substantially between 50% and 95% by weight of the fiber material; and

the formed composite strands comprise substantially between 5% and 50% by weight of the matrix material.