LEASH

BACKGROUND OF THE INVENTION
1. Field of the Invention

The present invention relates to leashes for watercraft used for surfing and other water sports such as body-boarding and stand-up paddle boarding. More specifically, the present invention relates to a cord construction that may be used within a leash assembly.

2. Description of the Art

There are various known arrangements and constructions for watercraft leashes. Watercraft may include surfboards, body boards, kiteboards and stand-up paddle boards (SUP) for example. A leash may be used between the watercraft user and the watercraft as described below.

Surfboard Leashes have become invaluable surfing equipment and the predominant method of tethering the surfboard to the surfer or watercraft user as well as other watercraft. By connecting the surfboard to the surfer, the watercraft user may experience many benefits; perhaps the most important of which being enhanced safety in the surf. A surfboard leash enables the surfer to be connected to the surfboard in the event of dismounting from the surfboard or experiencing a “wipe-out”. In doing so, the surfer is not left stranded without a flotation device in dangerous conditions which may be a significant distance from the shoreline. By facilitating the ability to quickly retrieve the surfboard after a wipe-out, the surfboard leash permits more time surfing and less time recovering the surfboard. It is also generally recognised that a surfboard leash may improve the safety of all surfers in the vicinity of the watercraft user by reducing the unrestricted movement of the surfboard or other watercraft, leading to less chance of surfboard damage, injury and drowning.

Conventional surfboard leashes are generally constructed with a cuff (or “ankle strap”) connected to an extruded Thermoplastic Polyurethane (TPU) cord. The cuff generally secures about an ankle of the surfer, typically using a hook and loop fabric fastener arrangement. The end of the TPU cord is normally over-moulded to mate with a swivel assembly that is housed within the cuff (on one end of the leash) and within a webbing strap, or “rail-saver” (at the other end of the leash) for connection to the surfboard. Both the cuff and the rail saver strap are generally constructed from Polypropylene/Polyester/Nylon webbing, neoprene and hook and loop fasteners using “cut-and-sew” manufacturing. Similar leashes may also be used for other watercraft and their users. For example for body boards the cuff may be secured about the bicep or wrist of the body-board user. SUP users may have the leash attached to their ankle.

TPU has traditionally been a suitable material for surf leash cords due to the combination of good strength and shock-absorbing properties at an acceptable cord thickness/diameter with respect to hydrodynamic drag and weight without exhibiting the high recoil or highly elastic properties of natural rubber, for example bungee cords or shock cords. When a surfer dismounts from a surfboard, wave/s can exert a significant force on the surfboard and the surf leash. To withstand these forces, it is necessary to select the appropriate TPU cord thickness for the prevailing surf conditions; thinner TPU cords (typically around 5 mm diameter) may mostly resist breakage on smaller waves, whilst thicker TPU cords (typically around 10 mm diameter) may usually resist breakage on larger waves. Leash cords with greater thickness create more hydrodynamic drag and weight; therefore the selection of thicker leash cords is normally restricted to larger wave conditions otherwise surfing performance may be adversely affected. Regardless of leash cord thickness, in order to absorb the shock transferred from wave to the surfer's ankle, it is desirable for a leash to provide dampening stretch. That is, the leash stretches so that an undue force is not applied to the surfer's ankle.

Typical TPU leash cords have an ultimate strength mostly determined by the TPU cord thickness/diameter. In order to construct a thinner leash cord from the same TPU (with lower weight and drag) it is necessary to reduce ultimate strength of the TPU cord and the higher, consequent likelihood of breakage or fracture of the cord. This reduction in cord diameter versus improved surfing performance may be an unacceptable compromise as this can result in the leash cord breaking prematurely and thus untethering the surfboard from surfer and increasing risk of injury and/or damage. It is desirable to have increased comfort and performance of the leash during surfing by a reduction in the thickness, weight and hydrodynamic drag of a surf leash cord without reducing the ultimate strength or shock absorption properties of the leash.

It is desirable for a surf leash cord to be as unobtrusive and tangle-free as possible in the water when paddling, sitting/waiting on the surfboard and when standing up surfing waves. Like any cord, existing TPU leash cords can be susceptible to tangling, which can be a frustrating, disruptive experience in the surf where performance and safety can suffer and untangling is necessitated. A longer leash length will increase the chances of tangling. The most common surf leash cord lengths are slightly longer than surfboard length. For example for many common short boards the leash may be 150 to 210 cm long (5-7 foot long) or even longer for modern longboards and SUPs. Similarly, a typical TPU leash that has experienced deformation (e.g. from creep when stress is held constant during shipping or storage, overstretching during use or other forces) is likely to feature kinks or inconsistencies along the direction of the length of the cord which may result in more irregular, less anticipated movement during use and thus increasing the chance of tangling. For example looping of the TPU about itself and/or the limbs of the watercraft user.

Whilst it is necessary for the TPU to stretch somewhat in order to provide shock-dampening, if the TPU leash cord stretches too much beyond the elastic limit the material will plastically deform. This results in the common problem of a leash “over-stretching” where a leash is permanently deformed or stretched beyond the original length. This may occur in use when the leash experiences a force beyond the elastic limit of the TPU cord, from say larger waves and/or a particularly vigorous wipe-out. It is not uncommon for TPU leash cords that have been repeatedly over-stretched in use to be permanently deformed to 2 or 3 times the original length of the leash cord. Not only is an over-stretched cord longer and more susceptible to tangling and interference during surfing and other watercraft use, the over-stretched cord also becomes thinner and weaker and thus reducing ultimate strength.

Typically TPU surf leash cords are constructed as one single extruded/moulded part with limited cut or abrasion resistance. Accordingly TPU leashes may be prone to damage and/or breakage during use. If the cord is damaged or cut during usage (such as abrasive and cutting interactions with rocks, reef, surf fins, tangling with persons or objects) then subsequent stretching may then propagate the damage/cut through the thickness of the cord and consequently reduce the ultimate strength of the leash. As a homogenous part, the traditional TPU surf leash cord is susceptible to a single failure mode whereby when the cord is damaged it is reliant upon resisting the propagation of the damage or fracture through the thickness of the cord. Accordingly such leashes are prone to catastrophic failure where hard to see knicks or cuts to the TPU cord may remain undetected until they fail in use.

None of these prior art apparatus, assemblies and methods provides an entirely satisfactory solution to the provision of a leash for a watercraft, nor to the improved safety of the use of the watercraft with a leash.

Any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates, at the priority date of this application.

SUMMARY OF THE INVENTION

The present invention aims to provide an alternative leash arrangement, assembly and/or method which overcomes or ameliorates the disadvantages of the prior art, or at least provides a useful choice.

In one form the invention provides a cord for a watercraft leash comprising: an elastic core, and a tubular over-braiding about the core, wherein the over-braiding is formed with a plurality of yarns that are less elastic than the core, and wherein the over braiding limits an extension of the core as the cord elongates.

The form of the over-braiding is selected to control and/or adjust an extension of the cord.

The core is formed of a plurality of core strands bundled by a tubular over-braid.

The core is a single elastic core.

The plurality of yarns are at least one of a higher tensile strength, higher ultimate break strength and higher fracture point than the elastic core.

In an alternate form the invention provides a leash for a watercraft comprising a cuff adapted to be attached about a limb of a watercraft user; a composite horn adapted to be secured by an extended base of the horn to the cuff; a securing strap to the watercraft; and an over-braided cord attached at one end to the cuff, via the composite horn, and at the other cord end to the securing strap.

The leash wherein the over-braided cord is as described herein.

The leash wherein the watercraft is at least one of a surfboard, a body board, a kite-board and a stand-up paddle board.

The leash wherein the composite horn comprises: a base extending longitudinally and at least partially circumferentially about a leash wearer's limb; a tapered horn extending from the base to a cord securing to a watercraft; and a core of a lower density material to a shell forming the base and the tapered horn.

The leash wherein the extended base and the elongated horn of the composite horn provide an increased stand-off distance between the cord and the leash wearer's limb to reduce a tangling.

The leash further including a rail-saver with a conformal overmould connection between a rail-saver strap end and the overbraid cord.

The leash further including a slip reducing arrangement of a plurality of protuberances applied to an inside face of the cuff.

The leash further including a pull tab with an erect loop configured to receive or grasped by a finger or thumb of a watercraft user.

In another form the invention provides a composite horn for a watercraft leash comprising: a base extending longitudinally and at least partially circumferentially about a leash wearer's limb; a tapered horn extending from the base to a cord securing to a watercraft; and a core of a lower density material to a shell forming the base and the tapered horn; wherein the extended base and the elongated horn provide a stand-off distance between the cord and the leash wearer's limb to reduce a tangling.

The horn increases a stand-off distance between a cord of the leash and a limb of a wearer of the leash.

In a further form the invention provides a rail-saver for a watercraft craft comprising: a first strap end adapted to secure to a watercraft; a connection between a second, other strap end and a cord attached to a watercraft user, wherein the second strap end connection includes a conformal overmould about the second strap end.

The rail-saver wherein the conformal overmould is formed or configured to reduce hydrodynamic drag.

The rail-saver or securing strap for a watercraft leash constructed with the strap end housed within a hydrodynamic moulded connecting part.

In yet another form the invention provides a slip reducing arrangement for a cuff of a leash, comprising: a plurality of protuberances applied to an inside face of the cuff that is secured to a limb of a watercraft user, wherein the plurality of protuberances aids at least one of securing and preventing movement of the cuff about the limb of the watercraft user.

A printed region on the inside facing of a watercraft leash cuff using a slip-reducing ink, polymer or rubber to increase a friction of the cuff about a limb of a user.

In a further form the invention provides a pull tab for a cuff of a watercraft leash, the pull tab comprising: a resilient erect loop attached to an outward face of the cuff, wherein the loop is formed to receive or grasped by at least one of a finger and a thumb of a watercraft user.

A hydrodynamic, moulded pull tab on the outer facing of a watercraft leash cuff that is configured to be naturally and resiliently receptive to the user's removal grip.

In yet another form the invention provides a termination for an over-braided cord comprising: splayed yarns of the overbraiding at an end of the overbraided cord are imbedded in an over moulding, wherein the overmoulding forms a termination suitable for coupling with a watercraft leash.

In another form the invention provides a surf leash apparatus comprising: a cuff for connecting to a surfer's body featuring an enlarged composite horn; and a cord connected via the enlarged composite horn to the cuff at one end and a surfboard at the other end.

A surf leash apparatus comprising: a cuff for connecting to a surfer's body featuring an enlarged composite horn; and an over-braided cord connected via the enlarged composite horn to the cuff at one end and a surfboard at the other end.

A surf leash apparatus comprising: a cuff for connecting to a surfer's body featuring an enlarged composite horn; and an over-braided cord constructed from a high strength braided outer portion and an elastic inner portion connected via the enlarged composite horn to the cuff at one end and a surfboard at the other end.

In an alternative form the invention provides a leash for a watercraft substantially as described herein with respect to the figures.

Further forms of the invention are as set out in the appended claims and as apparent from the description.

DISCLOSURE OF THE INVENTION
Brief Description of the Drawings

The description is made with reference to the accompanying drawings, of which:

FIG. 1 is a schematic drawing of a perspective view of a surf leash assembly with an over-braided cord and elongated composite horn.

FIG. 2 is a schematic diagram of a perspective view of a partially exploded, end sectioned over-braided cord with multiple elastic cores.

FIG. 3 is a schematic diagram of an alternative, single elastic core over-braided cord to FIG. 2.

FIGS. 4 and 5 are schematic diagrams to alternate outer sheath cords to those of FIGS. 2 and 3.

FIG. 6 is a schematic diagram of a tensile force versus elongation graph for a leash cord from the prior art, a bungee cord and the invention described herein with respect to FIGS. 2 and 3.

FIG. 7 is a schematic diagram of the elongated composite horn of FIG. 1, with a closed cuff assembly ghosted as dashed lines.

FIG. 8 is a schematic diagram of an alternative composite horn to FIG. 7.

FIG. 9 is a schematic diagram of a longitudinal cross-sectional view of the alternative composite horn and cord termination of FIG. 8.

FIGS. 10 to 12 are a sequence of schematic perspective view diagrams to the steps or process used to terminate the over-braided cord

FIG. 13 is a schematic diagram of a perspective view of an alternate hydrodynamic rail-saver with enclosed strap end housed in moulded assembly.

FIG. 14 is a schematic diagram of a longitudinal cross-sectional perspective view cross section of FIG. 13.

FIG. 15 is a schematic diagram of an alternate cuff with a selectively printed region/s of projections/protuberances on the cuff inside face or surface. A pull tab to the outside face of the cuff is also shown.

FIG. 16 is a schematic diagram showing the alternate cuff of FIG. 15 about a limb at the ankle of the watercraft user.

FIGS. 17 to 20 are schematic diagrams to respective front, side, top elevational and perspective views of a preferred Pull Tab geometry or arrangement.

In the figures the reference numerals are prefixed by the figure number. For example FIG. 1 is the “100” series, FIG. 2 is the “200” series and so on.

DETAILED DESCRIPTION

A surfboard or other watercraft leash assembled with an over-braided cord is described in the following. This over-braided cord construction improves on traditional Polyurethane or TPU leash cords by increasing break strength and cut resistance, decreasing thickness, weight and hydrodynamic drag and limiting over-stretching without sacrificing stretch and shock dampening. That is an over-braided cord construction provides for a thinner, lighter, stronger, more cut-resistant surf leash with reduced drag and limited over-stretching. In addition, the over-braided leash cord may include a plurality of elastic strands over-braided with a high tensile yarn to form a composite cord construction. The ultimate strength of the cord is related to the ultimate strength of both the elastic strands (core) and over-braid (sheath).

FIG. 1 is a schematic diagram of a perspective view of a surf or other watercraft leash assembly 110 with an elongate, tapered, enlarged and composite horn 112 as well as an over-braided cord 114 formed as described below with respect to FIGS. 2 and 3. The leash includes an ankle cuff assembly 116 with hook and loop fabric/textile fastening for securing a limb of the surfer or other watercraft user to the leash 110. The ankle cuff assembly 116 may have a slip-reducing print or pattern (not shown) on the inside surface 117 of the cuff facing and against the limb of the watercraft user in use. The slip reducing print or pattern is described further below with respect to FIGS. 15 and 16. The cuff 116 may also feature a hydrodynamically shaped, pull tab 119 as described further below with respect to FIGS. 15 and 17 to 20. The pull tab 119 may be used by the watercraft user to undo the cuff by pulling upon the pull tab with a finger inserted into the pull tab aperture 121 or by grasping the erect loop with two fingers. The ankle cuff assembly 116 has attached to it or includes an enlarged composite horn 112. The composite horn 112 is connected to the over-braided cord 114 by a swivel assembly 118. The other end of the cord 114 may also have another swivel assembly 120. The respective ends of the over-braided cord 114 may be terminated 122 by means of crimping, knotting, an end knot, over-moulding or other type of end terminating as described herein and housed on each opposing end within a swivel assembly 118, 120. A surfboard (not shown) may be connected to the leash 110 by means of a webbing strap, “rail saver” or securing strap 124 which includes a rope loop 126 for threading through and connecting to a surfboard leash plug. An alternative rail-saver is described further below with respect to FIGS. 13 and 14.

The composite horn 112 may be formed of a strong shell or exoskeleton 130 made from a suitably rigid Thermoplastic Polyurethane or other suitable material to provide stiffness, strength and absorb shock. A foam core or otherwise low density material for the inner part 132 of the composite horn 112 may be made from a lightweight polyurethane (PU) foam to reduce the weight and/or torque to the cuff 116.

FIG. 7 is a schematic diagram of the enlarged composite horn of FIG. 1; with the closed cuff assembly 116 ghosted as dashed lines. The enlarged composite horn 112 has a base 128 which is suitably attached to the cuff 116, for example by stitching, adhesives and/or moulding. The base 128 extends circumferentially about the cuff and limb of the watercraft user. As shown in FIG. 7 the shell of 130 at the base 128 extends further about the cuff than the foam core inner part 132. The arc shape of the base 128 together with a choice of suitable material flexibility and/or elasticity for the shell 130 allows the cuff 116 and base 128 to fit around the ankle better and with a more conformal fit to the ankle or other limb parts for other watercraft users. Horn bases of the prior art leashes are typically either flat ended plates for cuff bonding/stitching or a simple base end with a fixture to be coupled to the cuff.

The base 128 may circumferentially extend 720 about the closed cuff circumference 722 by approximately 15% to 45%. Preferably the base 128 circumferential extent is approximately 20% of the closed cuff circumference 722. The extended base circumferential form may have an arc shape suitable for a range of the surfer population, for example different extended bases adult male, adult female and juveniles. The extended base 128 may have a width 713 that extends to substantially the same width of the cuff 116 so as to also provide more support along the longitudinal direction of the user's limb. Also the extended base 128 may be formed of a plastic which readily bends when the cuff 116 is strapped about the limb of the watercraft user in order to provide better forming and comfort to the user as described above. The extended base 128 of the horn 112 provides extended support and load spreading to the limb for the considerably longer horn 112 of the invention as described below.

The lightweight, strong construction of the composite horn 112, allows a length 134 of the tapered horn to be substantially increased. The increased length of the horn may be done to increase a stand-off distance 134 between the wearer's limb and the cord 114 without sacrificing the described benefits of the enlarged composite horn. The elongated horn 112 may have a length 134 in the preferred approximate range of 80 to 100 mm that may depend on the size of the wearer and the length of cord. For example longer cords for longer surfboards may require greater stand-off distances of. Other approximate ranges for the horn length 134 may be from 25 to 150 mm or an approximate range may be from 80 to 150 mm, for example approximately 90 mm, or an approximate range of 25 to 80 mm. The length 134 of the horn 112 may also be defined with respect to a ratio of an extended base circumferential dimension 720 and the horn length 134.

It will be readily appreciated that whilst some prior art leashes may have a TPU over-moulding that provides some stand-off to the cuff; this is not a durable rigid section in the form of the tapered horn described herein. The TPU over-moulding in prior use does not support or maintain a stand-off distance as it is prone to distortion in use.

Whilst a range of dimensions and scaling of the enlarged composite horn 112 and extended base 128 have been described herein, it will be readily appreciated that a one size fits all approach may also be applied for the dimensions. The dimensions or relative values of the dimensions of the invention are increased compared with the prior art to achieve the functions of the enlarged composite horn as described. The relative values of the dimensions of the composite horn may be scaled with respect to prior art cuff dimensions and/or the limb of the watercraft user as well as average values for a one size all/universal fitting approach.

The composite horn form of composite construction, extended base and elongated, tapered horn offers a substantial improvement over traditional surf leash swivel connections and TPU over-mouldings to the cuff by creating a larger, stiffer, stronger base 128 which spreads the load over a larger area of the ankle cuff 116 and also reducing failure from point loading. The use of the composite construction for the horn of a shell or exoskeleton 130 with the foam core inner part 132 allows an elongated and tapered horn to be used which does not impose a significant or noticeable weight penalty. The extended horn length 134 also creates greater clearance/stand-off distance 134 of approximately two to eight times that of prior art leashes for the cord 114 away from the ankle. This increased stand-off distance considerably reduces the chance of the surf leash tangling around the ankle. In addition the composite horn construction allows for different materials to be used between the horn 112 and the over-braided cord 114 which is not possible with the prior art unitary process for TPU over-moulding of the prior art cord. For example the shell 130 material may be of a more rigid and shape durable resin than what is used for TPU over-moulding of the prior art cord.

FIG. 8 is a schematic diagram of a perspective view of an alternative composite horn 812 of the same composite construction as the tapered, elongate composite horn 112 of FIGS. 1 and 7. In a similar manner as described with respect to FIGS. 1 and 2, the alternate composite horn 812 is attached to the over-braided cord 114 via a swivel 118 and an alternate cord termination 822. The join 826 or moulding between the swivel 118 and the alternate composite horn 812 may be waisted if additional flexibility is desired whilst maintaining stiffness along the overall assembly of the alternate composite horn 812 and alternate cord termination 822. It will be readily appreciated that the overall assembly of the alternate composite horn 812 and alternate cord termination 822 may also provide an increased stand-off distance 134 and other advantages and performances as described with respect to FIGS. 1 and 7.

FIG. 9 is a schematic diagram of a longitudinal cross-sectional view of the alternative composite horn 812 and cord termination 822 of FIG. 8. In FIG. 9 the shorter alternate composite horn 812 length compared with the elongate tapered composite horn 112 of FIGS. 1 and 7 is shown. FIG. 9 also shows the alternate cord termination 822 in cross-section, featuring a tapered high-strength housing 926 that houses a potted over-braided cord end termination 928. The alternate cord termination 822 and the potted over-braided cord end termination 928 are described below with respect to FIG. 10.

FIGS. 10 to 12 are a sequence of schematic perspective view diagrams to the steps or process used to terminate the overbraided cord 114 using a potted terminal 928 within a high strength, tapered housing 926 to form the alternate cord termination 822.

Step 1 of FIG. 10 shows the high-strength housing 926 strung onto the cord 114 away from the frayed terminal end 1036 of the cord 114. The tapered housing 926 is preferably constructed from a resilient material with sufficient strength to withstand high loads and break force for a watercraft leash in use. For example the tapered housing material may be a Nylon. The end of the overbraided cord is intentionally frayed 1038 such that the over-braiding yarn 216 is splayed or otherwise teased out in an ordered and/or disordered fashion. In addition the fibres making a yarn 216 may also be splayed or teased out. The splayed yarn 1038 frayed terminal end 1036 is shown in an idealised layout in FIG. 10. The splaying of the yarn 1038 of the over-braiding is done to increase an over-moulding bond to both the splayed over-braid 1038 and the core 215, 315.

Step 2 of FIG. 11 shows an over-moulding or potting 1140 of the frayed terminal end region 1036 of the overbraided cord 114. The over-moulding is preferably a thermoplastic material such as TPU which provides a superior and substantial bond to the elastic core 215, 315, the frayed overbraiding/splayed yarn 1038 and encases the sheath of overbraiding 218, 318 away from the frayed terminal end region 1036. The over-moulding forming may also include a suitably formed recess or otherwise for a swivel assembly to be formed into or affixed after over-moulding. A swivel fixing through hole 1142 may be formed or otherwise provided to aid in securing the swivel to the over-moulding 1140 and the tapered housing 926. Alternatively to over-moulding or injection moulding, a potting resin to a suitable mould or the tapered housing 926 as a mould may be done. The splayed yarn 1038 that is intertwined, imbedded or otherwise dispersed through the matrix of the overmoulding material and or potting resin also provides superior coupling between the cord 114 and the alternate cord termination 926 that is coupled to the swivel 118 and the composite horn 112, 812.

It will be readily appreciated that whilst step one and two have been described with respect to a sheath of overbraiding 218, 318, the same technique may be applied to textile/fabric sheath as described with respect to FIGS. 4 and 5.

Step 3 of FIG. 12 shows where the tapered housing strung on the cord 114 is moved in the direction of arrows 1144 to sleeve the over-moulding 1140 or potted construction of FIG. 11. It has been found that under the extensive testing, described below, that the use of an over-moulding or potted construction to the splayed yarn 1038 of the frayed terminal end of the over-braided cord 1036 provides a more durable alternate cord termination 822 than alternate techniques of crimping or knotting of the cord or elastic cores. Furthermore it has been found that at extensive repetitive testing at higher forces that the alternate cord termination 822 is superior to alternate cord termination techniques. The addition of the tapered housing 926 as described above may also further increase the performance and durability of the alternate cord termination.

FIGS. 2 and 3 are schematic diagrams of perspective views of over-braided cords 214, 314 formed by over-braiding multiple elastic cores 215 or a single elastic core 315. The over-braiding or sheathing in FIGS. 2 and 3 is shown in the foreground of the diagram as partially exploded to show an arrangement of over-braiding. In FIGS. 2 and 3 a high tensile strength yarn 216 may be used to form a tubular braid 218, 318 about multiple elastic core filaments 215 in FIG. 2 or the single elastic core 315 of FIG. 3.

FIG. 3 shows the sheathing or over-braiding of an elastic Polyurethane core inner portion 315 to form an over-braided cord in a similar manner to the actual manufacturing process of the cord 314, whereby the sheath 318 is braided over the core using conventional kernmantle rope manufacturing machines calibrated or adapted for the novel and inventive use of this unconventional core 315 material together with the over-braiding yarn 216. When this finished over-braided cord 314 is under tension, both the properties of the outer portion 318 tubular over-braiding and the inner portion 315 elastic core combine to provide a surprisingly useful and improved stretch or elongation that is intentionally limited by the lower mechanical movement of the outer portion 315 outer-braiding which also provides the higher ultimate breaking strength (when compared to the inner portion). The stretching or elongation of the over-braided cord is described further with respect to FIG. 6.

In FIG. 2 the multiple elastic strands 215 form the elastic core bound by the tubular outer braiding 218. The use of multiple elastic strands 215 may help resist cord kinking better by being relatively less susceptible to creep (such as deformation resulting from constant multi-directional stress occurring during shipping, storage, use, etc.). Resistance to kinking is an important improvement to a surf leash cord as the movement of the leash is less predictable when there are kinks in the leash and can sometimes lead to tangling. Tangling about the limbs or neck of the user and/or within the leash may be an uncomfortable and dangerous experience in the surf. The cord 214 of FIG. 2 may also be manufactured as described above for FIG. 3 with further novel adaptations for the multiple elastic strands 215.

Various materials may be used to form the over-braided outer portion 218, 318 and the inner portions 215, 315 of the elastic cores. The yarn 216 for the over-braiding should have a high tensile strength to reduce premature breakage of the combined over-braided rope 218, 318. The high strength yarn may be a High Tensile Polyester, Nylon or UHMWPE (Dyneema). A yarn may also be made up of many filaments or fibres. This outer portion over-braiding may be placed or sheathed over the inner portion elastic core/s 215, 315 by means of an over-braiding manufacturing process common to kernmantle rope and bungee cord production, as depicted in the exploded portions of FIG. 2 and FIG. 3 and described above. For example each yarn of the eight shown is braided such that a yarn goes over then under an adjacent yarn in the fashion as shown in FIGS. 2 and 3. As such, the outer portion is constructed from multiple High Tensile yarn ends to form the over-braid. However, the inner portion core provides the stretch and shock dampening required in a surf leash (without stretching too easily so as to create fast, dangerous recoil back to the surfer) and therefore is constructed from a Thermoplastic Polyurethane (TPU) or similar, suitable elastic material (such as EPDM rubber, Silicone, etc.). Preferably an over-braid may be constructed from sixteen ends or yarns of 2,000 Denier Industrial Polyester fibre. Preferably an inner core may be constructed from approximately 10 to 20 elastic strands of extruded Shore A 95 Thermoplastic Polyurethane (TPU) of individual strand diameter of preferably approximately 1 mm. An approximate range for the selection of individual elastic strand diameters may be from 0.5 to 2 mm. Preferably 18 strands of TPU may be used for the elastic core strands 215. This preferred example of the over-braided cord 214 is referred to in FIG. 6 below for a comparative testing to a prior art leash.

It is evident from FIG. 2 and FIG. 3 that there are multiple strands and yarns, within the core and sheath of over-braiding, that form the rope or cord. In contrast to conventional, prior art surf leash cord construction which is traditionally manufactured from one single TPU extrusion. The multiple strand and yarn construction of the invention provides multiple failure modes, so that if one elastic strand and/or yarn is damaged or severed the performance of the leash may still be preserved by the remaining elastic strands of the core and/or yarns of the over-braiding. This is a substantial novel and inventive performance improvement over traditional surf leashes which have single failure modes whereby minor damage, such as a surface cut, may easily propagate to immediate failure during a surfing session. As the outer braid 218, 318 is constructed from a more cut resistant material than Polyurethane (such as High Tensile Polyester yarn), this further improves cut and failure resistance.

Different geometries may be employed to construct the inner portion (core) 215, 315 of the cord. In addition to the inner portions 215 and 315 described above with respect to FIGS. 2 and 3, a variety in the number of elastic strands and the geometric profile of these strands may be used to create the cord. For example, the extruded profiles do not need to be circular. For example the elastic strand transverse cross-sectional profiles may be oval, triangular, etc., or otherwise as long as they are arranged effectively to form a cohesive, elastic core during the over-braiding process. That is the multiple strands of the elastic core are arranged in a close packed arrangement that is tightly bundled by the over-braiding. Similarly, the number and diversity of different core strands may be varied to produce similar results to the preferred 10 to 20 strand example described above. For example, 1 to 10 elastic core strands may produce similar or different rope/cord characteristics. One elastic core with over-braiding may perform as described above for FIG. 3. However for a two elastic strand core the connection or conformability to the sheath/over-braiding may be substantially reduced. The use of fewer elastic strands in the elastic core may also provide less failure resistance compared with the preferred multi-strand elastic core. Using greater than 20 elastic strands to form the core may produce similar rope/cord characteristics; however this may add unnecessary complications to the manufacturing process without a substantial improvement in leash performance.

The performance of the elastic core with respect to strength and shock dampening may also be selected by considering an appropriate hardness, described on the Shore A scale, for the elastic core within the over-braiding. TPU may be used as an appropriate elastomer for the core material of the invention described herein due to the elongation properties and performance within the prescribed or described environment. The environmental factors may include: robustness in salt water, UV resistance, etc. and the like for the use of watercraft. A Shore A hardness range of 80 to 100 is considered appropriate for the inner portion of the over-braided rope/cord due to the sufficient shock dampening properties for the performance of the invention. The preferred value of Shore A 95 provided above may be considered an optimum for the cord construction described for that example. A lower Shore A hardness range elastomer, for example a Shore A hardness range of 20 to 70 which is common in natural rubber bungee cords, is not appropriate because the elongation at lower forces would be too high, providing insufficient shock-dampening and dangerous recoil. Likewise, an elastomer harder than the preferred useful range of approximately Shore A 80 to 100 may not provide enough shock-absorbing elongation, such that the recoil or contraction of the cord transfers too much force directly to the surfer, providing an uncomfortable and potentially dangerous interaction between the returning watercraft and the watercraft user. For example a hardness greater than Shore D 60 for an elastic core may be unsuitable for use. It will be readily appreciated that other elasticity related properties to hardness may also be used to define and specify the desired performance and selection of the elastic core material.

The over-braiding of the elastic core 215, 315 of the cord 114 may also be varied to change the properties of the cord with respect to elongation and contraction/recoil. The form of the over-braiding, the yarns used, the number of yarns, the yarn tension applied during over-braiding and the like may be selected and varied to control and adjust the elongation and/or contraction of the novel leash assembly system. Similarly the selection of the multiple elastic strands 215 and their arrangement together with how they may be over-braided may also be used to adjust and control the elongation and/or contraction.

An alternative construction to over-braiding to sheath or cover the inner portion of the elastic core may include assembling the outer portion/sheath by wrapping, weaving, stitching together a fabric or textile tube and inserting the elastic cord into it. FIGS. 4 and 5 schematically illustrate such alternative constructions. In FIGS. 4 and 5 a high tensile textile/fabric outer portion/sheath 418 sheathes a single elastic core inner portion 315 of FIG. 4 or an elastic core with multiple strands 215 in FIG. 5 to achieve similar characteristics to an over-braided cord. However, this may not be the preferred construction as over-braiding creates a tighter bond between sheath and core (reducing cord thickness) during elongation and contraction as well as being a more reliable, seamless construction method.

The alternative sheathing for the alternate cords 414, 514 described with respect to FIGS. 4 and 5 may also provide dramatically improved abrasion, cut and failure resistance compared with a TPU only prior art cord. The over-braided sheath 218 to the elastic core 214, 314 though may provide a superior failure resistance to the alternate sheathing 418 of FIGS. 4 and 5.

FIG. 6 is a schematic diagram to a tensile force versus elongation graph for a leash cord from the prior art, a bungee cord and the invention described herein. The origin of the graph corresponds to zero force and the original length of the leash. The elongation has been normalised to the original length of each leash cord, accordingly the ×5 elongation on the x axis corresponds to a leash cord which has been elongated to five times its original length. Each of the two leash cords 620, 622 shown in FIG. 6 were tested to the fracture point of the cord as well as the bungee cord 624. FIG. 6 contrasts typical results for a prior art leash cord and the over-braided cord of the invention. An over-braided cord according to the preferred invention is shown as line 620 on the graph. A traditional, prior art TPU leash cord of 5.5 mm diameter is shown by the line 622. A prior art bungee cord is shown by the line 624. When compared with a traditional TPU leash cord 622 of similar diameter, the over-braided cord 620 can withstand a higher ultimate force with considerably lower elongation.

The over-braided construction of the invention has the added benefit of limiting the plastic deformation (permanent, irreversible deformation from stretching) of the cord through the lower elongation, but higher tensile strength, of the outer-braid material. Over-stretching/plastic deformation is a common problem with traditional Polyurethane leash cords because the unwanted additional leash length can increase tangling (which is irritating and potentially dangerous to the surfer). For example prior art leash cords during testing as done for FIG. 6 often permanently elongate to over twice their original length. Considerable plastic deformation 626 of the traditional TPU cord 622 in FIG. 6 has occurred compared with the cord of the invention. The traditional leash 622 has permanently increased its length at a much lower tensile force than the over-braided, multi-strand elastic core leash 214, 620 of the invention.

The present invention is a substantial improvement on the prior art by reducing the over-stretching/plastic deformation problem and providing a higher ultimate break strength/fracture point. Whilst not wishing to be bound by theory the over-braiding may surprisingly only limit the elongation of the over-braided cord 114 for approximately the last 10 to 20% of the elongation. Accordingly the over-braiding may act to limit or arrest the elongation of the elastic core 214, 314 to less than the plastic deformation. The over-braiding may also act to limit the elongation of the elastic core so that it does not reach a tensile force fracture point for the elastic core. That is during the elongation of the over-braided cord there may be a staged engagement of the elastic core and then the over-braiding sheath as the elongation and force applied progresses.

The commercially available rubber-core Bungee Cord 624 shown may also have a different type of over-braided sheath. The Bungee cord 624 has an elastic elongation of up to ×2.5 for a very low tensile force compared with the cord of the invention. In addition a fracture point 628 of the bungee cord is very low compared with the two leashes 620, 622 shown in FIG. 6. Clearly such elastic rubber-core bungee cords are very unsuitable as a surf leash cord (or other watercraft) because the elastic rubber core provides too much elongation at low forces; resulting in insufficient shock dampening and dangerous recoil. In addition, rubber-core bungee cords generally do not have sufficient break strength to be used as surf or watercraft leashes. Predominantly for these two reasons; the inventor(s) are unaware of any commercially available bungee cord surf leashes.

In addition bungee cords may have different over-braiding with less yarn. For example the less yarn may be in terms of the number of yarns used in an over-braiding and/or the number of fibres/filaments in each yarn. Typically the yarn for bungee cords may be a lower cost and substantially lower tensile strength synthetic yarn compared with the higher tensile strength yarns used for the invention. For example the yarn material for bungee cords may be a low cost polypropylene. The bungee cords may also be constructed with a different over-braiding pattern to that described with respect to FIGS. 2 and 3. A different over-braiding pattern or arrangement may be used for bungee cords to provide more elastic elongation, for example as shown in FIG. 6 for the bungee cord 624 in comparison to the watercraft leash cords 620, 622.

The FIG. 6 graph also serves to highlight that whilst both Bungee Cords and the present invention utilise a type of over-braiding, the unique combined material properties of the present invention provides a superior cord to be used within a surf leash assembly due to the lower elongation (particularly at low force), different hysteresis and higher ultimate break strength achieved with a cord of smaller thickness, lower weight and lower hydrodynamic drag.

FIG. 13 is a schematic diagram of a perspective view of an alternate rail-saver 1324. The rail saver 1324 has a strap 1346 with a strap first end 1348 that typically attaches to the watercraft via the rope loop 126 as shown in FIG. 1. A second, other end of the strap 1350 is connected to the alternate cord termination 822 by a conformal over-mould connection 1352. The conformal over-mould 1352 may be formed about or made suitable to sleeve over the second strap end so as to provide a low hydrodynamic drag form or configuration. The overmould 1352 may fully enclose the second 1350 end of the securing strap 1346. In addition the width of the strap 1346 and the conformal overmould 1350 may also be narrower than other rail-savers, for comparison as shown in FIG. 1, so that the reduced width of the strap 1346 and conformal overmould 1350 is closer or substantially the same as the diameter of the swivel 118 and an end of the alternate cord termination 822. Such a reduced width of the strap 1346 and overmould 1352 may also contribute to the reduction in hydrodynamic drag.

FIG. 14 is a schematic diagram of a longitudinal cross-sectional perspective view of the second strap end 1350 within the sleeving, conformal overmould connection 1352. In use the conformal overmould connection 1352 form and/or configuration may provide a smooth transition in dimensions and profile along the length of the rail-saver to minimise or reduce hydrodynamic drag in this region of a leash. In other words the railsaver is more hydrodynamic because instead of being constructed by a webbing looping around the swivel assembly/swivel assembly overmould, the webbing end of the strap is enclosed in the swivel assembly conformal overmould connection, enabling the surrounding swivel overmould geometry to be less square and more hydrodynamic.

The second strap end 1350 may be secured within the conformal over-mould 1352 connection by through stitching (not shown) or other suitable fastening means.

FIG. 15 is a schematic diagram of an alternate cuff 1516 with a selectively printed region/s of projections/protuberances 1554 on the cuff inside face or surface 117. The protuberances provide a slip reducing arrangement to the inside face 117 of the alternate cuff 1516. The pattern of protuberances on the inside surface 117 against the skin of the watercraft user may be used to increase the friction of interaction and coupling between the cuff inside facing surface 117 and the limb or wetsuit of the watercraft user. The use of the pattern of protuberances may reduce a slippage, a twisting around the ankle or limb, as well as movement of the cuff 1554 up and down the ankle region without the need for an excessively tight application of the cuff 1516 about the limb. The selectively printed region or pattern of protuberances may be printed or otherwise applied using an ink, polymer, resin or rubber such as silicone that has relatively high elasticity and a favourable friction coefficient to promote greater friction or grip when secured to a limb or against the skin or wetsuit of the watercraft user.

FIG. 16 is a schematic diagram showing the alternate cuff 1516 of FIG. 15 about a limb at the ankle 1656 of the watercraft user. The cuff 1516 outline is shown in dashed lines to improve the clarity with respect to the protuberances 1554 adjacent and into the skin 1658 of the watercraft user. The increased surface area between the selectively printed region 1554 of protuberances 1554 and the unprinted regions with the wearer's limb create a greater frictional bond or interaction and mechanical engagement with the skin and limb to reduce slipping. Prior art leashes without this print or pattern of protuberances may exhibit much more movement about the ankle during use; especially during wipe-outs where this movement leads to reduced comfort and increased tangling of the cord and of the cord about the limbs due to inappropriate positioning of the horn and cord about the ankle of the watercraft user. It will be readily appreciated that the artwork for this slip-reducing print can take on many variations of patterns, including the configuration described in FIG. 15 whereby each printed circle with a naturally domed surface keys into the skin or wetsuit of the user's limb, increasing the surface area interaction. The shape of the protuberances may be varied as convenient for a particular application technique to the inside face 117 of the cuff.

FIG. 15 also shows a moulded pull tab 1556, 119 which may be fixed by stitching or similar method to the outer face 1558 of the cuff 116, 1516 to enable quick, easy, guided removal of the cuff 1516, 116 from the limb. The moulded pull tab 1556 in its relaxed or normal state allows the watercraft user's finger or thumb to readily engage and or enter the loop aperture 1560 to enable the fast and easy removal of the cuff. Alternatively the use of the erect loop 1562 facilitates grasping with a finger and thumb. This is particularly useful in dangerous situations that might warrant the quick removal of the cuff such as when the leash may be caught or snagged on an underwater reef. The pull tab 1556 may be moulded from a suitable material that is strong enough to withstand pulling but pliable enough to be comfortable about the ankle such as TPU. Unlike prior art pull tabs constructed from naturally flat materials, the moulded pull tab 1321 is in the form of an erect loop 1562 that withstands the movement of the user and the flow of water as well as being resiliently receptive to user engagement by a finger and/or a thumb. The pull tab geometry is minimal in form and footprint in order to reduce weight and hydrodynamic drag. The erect loop 1562 of the pull tab 1556 may as one option be secured to the cuff by a ring 1564 which may be stitched or otherwise secured to the outer face 1558 of the cuff 1516, 116.

FIGS. 17 to 20 are respective front, side, top elevational and perspective views of a preferred Pull Tab geometry or arrangement.

In addition to field testing of the leash invention in surf conditions, the inventors utilised a variety of methods to test the forces on the present invention and to compare with prior art surf leashes and leash components constructed with different techniques. A wide range of elongation speeds were tested from repetitive slow elongation using winch systems to fast elongation using sandbag pulley system arresting drop tests. These tests may be completed over many repetitions or cycles to surprisingly discover issues not present in single testing that may be commonly used. For example, weaknesses with crimping cord end termination and issues arising from over (or under) extended TPU cord during the over-braiding process has been discovered through repetition testing.

Surprisingly the inventors have noted that during the prototyping and development of the invention to an over-braided cord with a combination of sheath and core materials specifically formulated for surfing conditions has resulted in a unique leash cord construction and performance leash that the inventors are unaware exists commercially in any industry. The novel cord construction and performance of the invention for a surf leash represents a considerable advancement of the current commercial surf or watercraft leash offerings. The commercial, prior art surf leashes being almost entirely of homogenous extruded/moulded Polyurethane surf leash cords.

The properties of the over-braided cord invention 110 include: increased break strength and cut resistance, decreased thickness, decreased weight and reduced hydrodynamic drag are complimented by the cord arrangement 114 with the hydrodynamic rail-saver 1122 and with the enlarged composite horn 112 which aids in adequately and evenly distributing the increased strength from the cord 114 to the ankle cuff 116 through the increased base 128 strength, extended base about the cuff and size of the composite horn 112. The additional length 134 and stiffness of the composite horn 112, 812 also encourages the trailing over-braided cord 114, 214, 314 to protrude further away from the ankle, reducing tangling around the ankle, therefore further enhancing the combined properties of the leash system/assembly 110.

It will be readily appreciated that most if not all the geometries and dimensions of the components of the watercraft leash assembly 110 invention described herein may be scaled up or down to better cater for the intended end user and/or specific surf conditions. For example, the components may be scaled down to further reduce the weight of the leash assembly for conditions that may withstand a reduction in strength such as small waves or surf competition. Conversely, the components may be scaled up or otherwise adjusted for greater strength in big wave conditions. Also, the components may be slightly modified in geometry to produce better sizing and fit for particular target markets such as male adult, women, children and athletes of watercraft users.

In this specification, terms denoting direction, such as vertical, up, down, left, right etc. or rotation, should be taken to refer to the directions or rotations relative to the corresponding drawing rather than to absolute directions or rotations unless the context require otherwise.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiments, it is recognized that departures can be made within the scope of the invention, which are not to be limited to the details described herein but are to be accorded the full scope of the appended claims so as to embrace any and all equivalent assemblies, devices, apparatus, articles, compositions, methods, processes and techniques.

In this specification, the word “comprising” is to be understood in its “open” sense, that is, in the sense of “including”, and thus not limited to its “closed” sense, that is the sense of “consisting only of”. A corresponding meaning is to be attributed to the corresponding words “comprise, comprised and comprises” where they appear.

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