Patent Grant
9220968
The embodiments of the present invention relate to an improved heel lock for use with splitboard boot bindings.
Splitboarding is unique in winter sports because it combines elements of skiing and snowboarding. A splitboard looks like a snowboard when fully assembled, but can be taken apart to be used as a pair of skis—the board is split lengthwise and each board half is a ski when separated. Splitboards typically include a ski binding interface and a splitboard binding interface such that a single pair of boot bindings is used to mount the rider's boots on either interface. Thus the rider can switch the bindings between a ski touring mode and a snowboard riding mode at will. In snowboard riding mode, with both feet spread apart on a board, the knee injuries that plague skiers are significantly reduced, but safety issues with ski touring mode remain.
In ski touring mode, there is a need for a fixed heel binding, for example when using climbing skins, when sidestepping up on steep slopes, and on a downhill ski run. A heel lock mechanism permits the rider to be more aggressive in turning and carving with the ski edges, improving performance. Wariakois in U.S. Pat. No. 5,984,324 suggested inserting a locking pin into the boot binding baseplate at the heel. However, skiing in this way, with no possible release, subjects the rider to risk of injury, such as an Achilles tendon tear or detachment. When the heel is locked to a ski, injury can result if the ski tip is levered toward the knee resulting in ankle hyperflexion, such that the heel tendon may be pulled from the calcaneus or torn in the hypovascular zone intermediate to the gastrocnemius. If the tendon is torn away with a bit of bone attached, the injury has a good prognosis, but soft tissue damage from a muscle or tendon tear typically takes a longer time to recover. Such tears may result in prolonged disability and the prospect of lifelong pain and weakness.
To reduce the safety hazard of locked heel skiing, skiers have developed alpine touring heel release technology. Breakaway mechanisms detach the boot at the heel when the torsional forces on the heel exceed a pre-selected threshold. The release threshold is adjusted according to the size, skill and physique of the user so as to prevent unnecessary release and sudden falls. A range of DIN settings is offered by each manufacturer and is dependent on a clamp that engages a hard boot worn by the rider.
Hard boot technology developed for skiing is not generally adapted for splitboarding because of the widespread preference for soft boots. Riders have increasingly opted to wear soft boots and use toe and ankle straps in combination with a heel cup to secure their leather boots to a baseplate. The baseplate is mounted on a toe pivot interface in ski touring mode or on a snowboard interface in snowboard ride mode. The baseplate can be rapidly interchanged between the two interfaces, and should also function for use with climbing bars and crampons. These complications dictate that any safety release mechanism for splitboarding is subject to a unique set of problems not encountered with alpine ski equipment.
Thus there is an unmet need for a splitboard boot binding means that will automatically disengage a rider's heel when the torsional force on the rider's foot exceed a safe level, but is otherwise stable and secure so as to avoid inadvertent and unnecessary disengagement. Also advantageous would be a release device that is readily reassembled and re-used after a release event, is easily engaged and disengaged with a ski pole or a gloved hand, is compatible with climbing bars and crampons, and—does not interfere with the essence of splitboarding, the capacity to easily switch between ski touring and snowboard ride modes.
Disclosed is a heel lock and release combination for use with splitboards in ski touring mode. The mechanism is synergic with existing ski touring and snowboard ride interfaces and with the soft boot baseplates preferred by splitboarders. A heel rest bracket with spring clamp is mounted on each ski under the rider's heel such that the spring clamp engages contralateral flanges or teeth on the underside of the baseplate and prevents heel release. The spring clamp is moveable between a first position in which it engages locking surfaces of the flanges (a “heel lock position”) and a second position in which the heel is unlocked (a “free heel position”). Surprisingly, a release threshold at 125 pounds of pull force (about 125 lb or 550 N) on the pivot tangent is high enough so as prevent inadvertent disengagement but is low enough so that the risk of injury is reduced.
To use the invention, the rider straps a soft boot on a baseplate mounted on a ski touring interface and engages the heel lock by engaging the spring clamp arms on the flange teeth of the baseplate. The baseplate is designed to pivot at the toe or may be locked to the ski using the spring clamp arms. A locked heel enables the rider to better transmit force applied during turns and carving when skiing. However, the heel lock is designed to reversibly snap free from the heel rest if a pull force on the ski or heel exceeds a safe level. Use of the heel lock assists the rider in avoiding serious injury to the Achilles tendon or gastrocnemius. A control or selector arm is supplied that allows the rider to move the clamp, such as with a ski pole, between the heel lock position and the free heel position according to conditions and skiing style.
Thus more generally, in a first aspect, the invention is an improved ski touring interface for use with a splitboard binding, the ski touring interface comprising a heel lock and release combination having a spring clamp configured to release the heel end of said binding when subjected to an unsafe critical pull force at the heel thereof. The invention is compatible with splitboards having dual interfaces for splitboard riding mode and ski touring mode. More particularly, a heel lock and release combination is added to the ski touring interface. The combination comprises a baseplate member having a toe pivot and an underside channel, the underside channel having an underside anchor tooth or teeth disposed at the heel end of the baseplate. The invention is further characterized by (i) a heel rest bracket mounted on each ski member under the heel end of the boot binding baseplate, and (ii) a spring clamp moveably positioned on said heel rest bracket; wherein the spring clamp is moveable between a heel lock position and a free heel position such that, in the heel lock position, the spring clamp is configured with an arm or arms to engage the underside anchor tooth or teeth, thereby locking the heel to the ski; and to release the heel from the heel lock position when a rider's heel is subjected to a critical pull force established as a safety threshold. The spring clamp of the heel lock and release apparatus is reversibly movable from the heel lock position to the free heel position by a rotating motion, a bending motion, or a sliding motion. In more particular embodiments, the heel lock and release apparatus for a splitboard ski touring interface comprises: (a) a boot binding baseplate having a toe end and a heel end, wherein said toe end is configured to attach to a toe pivot of a ski touring interface and said heel end comprises contralateral anchor teeth disposed inferiorly thereon, said anchor teeth having a defined lateral separation distance; further characterized by (b) a spring clamp body configured to attach to a ski member of a splitboard under the heel end of the boot binding baseplate, the spring clamp body having a heel lock lever or tab for moving the spring clamp body from a free heel position to a heel lock position and two spring arms conjoined thereto, each spring arm having a tip end, wherein the tip ends are configured to span the lateral separation distance when engaged on the anchor teeth in the lock position; and, wherein the spring clamp arms are elastically deformable, such that the tip ends are enabled to disengage from the anchor teeth when a toe pivot force on the anchor teeth exceeds a release threshold. The leaf spring clamp is formed of a folded spring steel. The tip ends seat on the anchor teeth in the lock position so as to clampingly prevent a pivot of the baseplate on the toe pivot when not stressed, and elastically deform so as to unseat from the anchor teeth when stressed by a toe pivot force exceeding a safety limit or threshold defined as a force below the tensile failure strength and stretchability of a rider's Achilles tendon. As experimentally determined, the preferred safety threshold or critical pull force is about 125 lb (556 N).
The elements, features, steps, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which presently preferred embodiments of the invention are illustrated by way of example.
It is to be expressly understood, however, that the drawings are for illustration and description only and are not intended as a definition of the limits of the invention. The various elements, features, steps, and combinations thereof that characterize aspects of the invention are pointed out with particularity in the claims annexed to and forming part of this disclosure. The invention does not necessarily reside in any one of these aspects taken alone, but rather in the invention taken as a whole.
The teachings of the present invention are more readily understood by considering the drawings, in which:
The drawing figures are not necessarily to scale. Certain features or components herein may be shown in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity, explanation, and conciseness. The drawing figures are hereby made part of the specification, written description and teachings disclosed herein.
Certain terms are used throughout the following description to refer to particular features, steps or components, and are used as terms of description and not of limitation. As one skilled in the art will appreciate, different persons may refer to the same feature, step or component by different names. Components, steps or features that differ in name but not in structure, function or action are considered equivalent and not distinguishable, and may be substituted herein without departure from the invention. Certain meanings are defined here as intended by the inventors, i,e., they are intrinsic meanings. Other words and phrases used herein take their meaning as consistent with usage as would be apparent to one skilled in the relevant arts. The following definitions supplement those set forth elsewhere in this specification.
“Splitboard”—when fully assembled a splitboard has the shape of a snowboard, but the board is split lengthwise down the middle and each board half is functional as a ski when separated. Splitboards typically include a ski touring interface and a splitboard ride interface such that a single pair of boot bindings is used to mount the rider's boots on either interface. Thus the rider can switch the bindings between a ski touring mode and a snowboard riding mode at will. In snowboard riding mode, the rider faces right or left and puts one foot in front of the other when strapping in. In ski touring mode, the rider's feet are generally centered on the ski members and move independently. Ski touring mode can include “free heel” skiing as is familiar to Telemark, skate ski and cross-country skiers, or Alpine skiing with locked heels.
General connection terms including, but not limited to “connected,” “attached,” “conjoined,” “secured,” and “affixed” are not meant to be limiting, such that structures so “associated” may have more than one way of being associated. In general, fasteners such as bolts and pins as would be known to one skilled in the art are omitted in the drawings for clarity.
Relative terms should be construed as such. For example, the term “front” is meant to be relative to the term “back,” the term “upper” is meant to be relative to the term “lower,” the term “vertical” is meant to be relative to the term “horizontal,” the term “top” is meant to be relative to the term “bottom,” and the term “inside” is meant to be relative to the term “outside,” and so forth. Unless specifically stated otherwise, the terms “first,” “second,” “third,” and “fourth” are meant solely for purposes of designation and not for order or for limitation. Reference to “one embodiment,” “an embodiment,” or an “aspect,” means that a particular feature, structure, step, combination or characteristic described in connection with the embodiment or aspect is included in at least one realization of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment and may apply to multiple embodiments. Furthermore, particular features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments.
It should be noted that the terms “may,” “can,” and “might” are used to indicate alternatives and optional features and only should be construed as a limitation if specifically included in the claims. The various components, features, steps, or embodiments thereof are all “preferred” whether or not it is specifically indicated. Claims not including a specific limitation should not be construed to include that limitation. The term “a” or “an” as used in the claims does not exclude a plurality.
“Conventional” refers to a term or method designating that which is known and commonly understood in the technology to which this invention relates.
Unless the context requires otherwise, throughout the specification and claims that follow, the term “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense—as in “including, but not limited to.”
The appended claims are not to be interpreted as including means-plus-function limitations, unless a given claim explicitly evokes the means-plus-function clause of 35 USC §112 para (f) by using the phrase “means for” followed by a verb in gerund form.
Representative ski touring and snowboard ride interfaces are described in more detail in U.S. Pat. No. 5,984,324 to Wariakois and in U.S. Pat. Nos. 7,823,905, 8,226,109 and 9,022,412 to Ritter. Alternate toe pivot assemblies usable with the invention are described in WIPO Pat. Appl. No. PCT/US2013/078477 to Ritter, which is co-owned and co-pending. Other suitable toe pivot assemblies for practice of the inventive heel lock means are described for example in US Pat. Publ. Nos. 2012/0274036 to Kloster and US2013/0341889 to Neubauer. All said patent documents are hereby incorporated herein in full by reference for all purposes. Generally, any toe pivot means for use in ski touring mode on a splitboard is compatible with the heel lock means of the invention. Conventional features of a boot binding, such as a toe and ankle strap, heel loop and highback, are shown for completeness but are not part of the heel lock and release mechanism of the invention.
The toe pivot assembly allows the rider's boot to pivot for free heel skiing, for cross-country, and for climbing in ski touring mode. The heel lock assembly is provided with a heel lock lever 2 for securing or releasing the heel end of the baseplate. A heel rest 6 is provided so that the baseplate is generally level from toe pivot end 12 to heel end 13.
In
In another option, a coil spring may be used to engage a heel locking lever that rides on an anchor tooth on the baseplate. A cam action results in release when the release force overcomes the restorative spring force of the coil spring. By the same principles, spring loaded jaws with a pincer action on the anchor teeth (or a transverse anchor bar) may also be used. These alternatives are configured to have in common the preferred release force threshold derived experimentally as disclosed here (see EXAMPLE 1 and
The anchor teeth are seen to be projections of a bottom flange that defines each side of an internal channel 26. This channel is dimensioned to receive the slider pucks; the flange interlockedly engages a mating flange on the outside edge of each slider puck (e.g., 105b) for a tight grip when wedged between the toe pivot assembly 3 and the anchor teeth (24a, 24b).
Advantageously, the stem bolt replaces a center screw of the heel rest bracket, so that the heel lock is a “bolt-on” retrofit and requires no modification of the splitboard or existing ski-mode hardware when used with a mating baseplate and heel rest. Thus the heel lock device may be sold as a kit and may be installed as an aftermarket upgrade by the rider without the need for drilling.
Drawn is a boot binding baseplate 210 in a “free heel position” 222 and a “heel lock position” 223, demonstrating the toe pivot action of the boot binding on the ski member (bold arrow). The boot binding baseplate includes a heel end 211 and a toe end 212 and is dimensioned to support a rider's boot. The heel lock and release assembly 201, a sliding heel lock lever or “selector tab” 202 and heel rest bracket 206 are shown in side view and are described in more detail in the following illustrations. As drawn here, the toe pivot assembly 203 includes a toe pivot cradle, toe pivot ears, a latch pedal and pintle pins as described in US Pat. Appl. Publ. No. 2014/0210187, titled “Boot Binding System with Foot Latch Pedal” which is co-owned and co-pending. Also shown is a cutline for the sectional plane depicted in
Unless locked, the baseplate is free to rotate at toe pivot ears 230. Pivot pins mounted in the toe pivot ears 230 of the baseplate engage pivot holes in a toe pivot cradle bracket 229 of the ski touring interface. But if the heel is locked down, any excessive pull force as the rider falls forward on the ski tip angles up will stretch the rider's Achilles tendon. Thus the need for a heel lock and release combination of the embodiments of the invention.
The heel rest bracket 206 is attached to the top surface 7 of the ski member. The bracket includes an underside channel for receiving the spring clamp body and permits the spring clamp to slide in and out so as to engage or disengage the anchor teeth. The bracket holds the spring clamp in place and resists any force applied to the spring clamp body unless the force exceeds a characteristic stiffness of the spring arms and tip ends 227b. Also shown in this view is a heel cup 2054. Not shown are conventional toe and ankle straps used to secure the rider's boot to the baseplate and an optional highback that provides additional ankle support.
Locking down the heel is also helpful in climbing, such as sidestepping up steep slopes or using climbing skins. The climbing skins may catch, causing the rider to pitch forward, and use of a heel lock stabilizes the rider and gives more control. Thus a solution to the issues of control and safety is presented by a heel lock mechanism that includes a safety release as provided here.
Also shown for comparison is a representative failure strain of a human Achilles tendon. Per literature reports, ultimate failure strain is about 1200 N (LOUIS-UGBO, J et al, 2004, Tensile properties of fresh human calcaneal (Achilles) tendons, Clin Anat 17:30-35). Failure strain was reported to be reached at about 9.9% of tendon length at 10%/sec, a relatively slow rate of extension (WREN, T et al, 2001, Mechanical properties of the human Achilles tendon, Clin Biomech 16:245-51). While not bound by theory, a rapid 10% extension over the lower 15 cm of isolated ligament is prevented by configuring a heel release with spring clamp release at about <1.5 cm of displacement. As currently practiced, release occurs with about 1.4 cm (˜0.56 inches) of deformation of the spring and would correspond to the entire bone/ligament/muscle complex. Taking the bone-tendon complex, failure strain occurs at 16.1%, suggesting a substantial safety margin, not including live muscle. Thus the experimentally derived value is within the range of biomechanical measurements made by Wren and Louis-Ugbo. The spring material is configured to release before an injurious biomechanical limit on extension is likely, while maintaining a practical degree of rigidity in the heel lock position such that inadvertent and premature release is not expected.
As the heel is pulled upwards, its displacement is opposed by the spring and if the pull force is below the release threshold, then the spring will recover, restoring the heel to its lock position against the ski. The performance of the heel lock is controlled by the dimensions, geometry, work hardening, and by the elastic modulus of the spring material. Analogous to the setup of
In yet other embodiments, the spring clamp is moveable by bending, such as the compression of a coil spring so as to engage a cam pin, whereby the coil spring will ride up on the cam pin as a release force is applied. In this embodiment, the critical limit for release is adjustable, as by a tightening action applied to the coil spring against the cam pin. However, field testing suggests that an optimal setting is around 125 lb and adjustments up from this threshold would only be appropriate for more skilled or physically fit riders.
A variety of metals were tried in order to discover a spring material that functioned properly. Further experimentation was then needed to determine a “release force” at which the heel snaps free. By trial and error, a release force of about 125 lb was found to offer a suitable compromise between safety and the inconvenience of suddenly having to catch one's balance or being flat on the snow when the heel lock releases. A series of spring clamp bodies having “folded” leaf spring arms of the kind shown in
All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and related filings are incorporated herein by reference in their entirety.
Having described the invention with reference to the exemplary embodiments, it is to be understood that it is not intended that any limitations or elements describing the exemplary embodiments set forth herein are to be incorporated into the meanings of the patent claims unless such limitations or elements are explicitly listed in the claims. Likewise, it is to be understood that it is not necessary to meet any or all of the identified advantages or objects of the invention disclose herein in order to fall within the scope of any claims, since the invention is defined by the claims and inherent and/or unforeseen advantages of the present invention may exist even though they may not be explicitly discussed herein.
While the above is a complete description of selected, currently preferred embodiments of the present invention, it is possible to practice the invention use various alternatives, modifications, combinations and equivalents. In general, in the following claims, the terms used in the written description should not be construed to limit the claims to specific embodiments described herein for illustration, but should be construed to include all possible embodiments, both specific and generic, along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2433161 | Schwarze | Dec 1947 | A |
| 2705150 | Hansen | Mar 1955 | A |
| 2823922 | Berlenbach | Feb 1958 | A |
| 2879071 | King | Mar 1959 | A |
| 3326565 | Cubberley | Jun 1967 | A |
| 3379447 | Webster | Apr 1968 | A |
| 3471161 | Cubberley | Oct 1969 | A |
| 3504923 | Berchtold | Apr 1970 | A |
| 3630539 | Lusser | Dec 1971 | A |
| 3630559 | Lusser | Dec 1971 | A |
| 3754769 | King | Aug 1973 | A |
| 3787062 | Kusianovich | Jan 1974 | A |
| 3893682 | Weinstein | Jul 1975 | A |
| 3908971 | Engel | Sep 1975 | A |
| 4522424 | Luitz | Jun 1985 | A |
| 4592568 | Priskich | Jun 1986 | A |
| 5271649 | Gromotka | Dec 1993 | A |
| 5518264 | Broughton | May 1996 | A |
| 5649722 | Champlin | Jul 1997 | A |
| 5697631 | Ratzek | Dec 1997 | A |
| 7681904 | Ekberg | Mar 2010 | B2 |
| 7823905 | Ritter | Nov 2010 | B2 |
| 7988180 | Holzer | Aug 2011 | B2 |
| 8033564 | Riepler | Oct 2011 | B2 |
| 8226109 | Ritter | Jul 2012 | B2 |
| 8328225 | Prigge | Dec 2012 | B2 |
| 8348299 | Ekberg | Jan 2013 | B2 |
| 8469372 | Kloster | Jun 2013 | B2 |
| 8708371 | Balun | Apr 2014 | B2 |
| 8764043 | Neubauer | Jul 2014 | B2 |
| 9022412 | Ritter | May 2015 | B2 |
| 9079094 | Eckberg | Jul 2015 | B2 |
| 20040187270 | Lee | Sep 2004 | A1 |
| 20080122202 | Furr | May 2008 | A1 |
| 20090072519 | Hutchinson | Mar 2009 | A1 |
| 20120274036 | Kloster | Nov 2012 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20150343298 A1 | Dec 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62007358 | Jun 2014 | US |
