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Scarpa Spring-Loaded Mode Lever

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  • Scarpa Spring-Loaded Mode Lever

    Last year I started a thread about some aftermarket spring-loaded walk mode levers from splitboard company Phantom, meant to make AT boot cuffs flex forward via spring compression rather than elastic deformation. It looks like Scarpa is cooking up something similar (full patent here).

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    From the patent:

    - "the present invention relates to a ski mountaineering or Telemark ski boot"

    - "Unfortunately, the dynamic behaviour of the [traditional] cuff locking device does not meet the requirements of some users that would like to allow the cuff to make small movements/ swings (no more than a few degrees) even when the cuff is locked in the downhill position, so as to at least partially facilitate the typical movements of the ankle during downhill skiing."

    - "Aim of the present invention is to produce a cuff locking device adapted to rigidly lock the cuff to the foot casing in the downhill position, while anyway allowing the cuff to make small movements with respect to the pre-set tilt."

    - "the cuff locking device 15 is moreover structured to oppose in elastic manner to the small swings of cuff 3 about the above mentioned downhill position.

    - "the elastic counteracting member 18 is preferably structured so as to be able to elastically bring and hold the movable arm 17 alternately and indifferently into the above mentioned lowered or locking position, and moreover also into a raised or unlocking position"

  • #2
    Notes/Thoughts/Wild Unfounded Speculation:

    Given that the patent specifically mentions "Telemark," this could be part of the new upper design described by Kim Miller in the recent Freeheel Life podcast (discussed here.)

    This is similar to the mode lever used for over a decade on the F1 and Alien boots, except that it doesn't pull double-duty by also tightening the cuff closures. The F1/Alien lever is held in the up ("free") or down ("locked") position by tension on the spectra line. The spring in this new design is configured to make the lever want to be in the up or down position. It won't just be flopping around.

    This design should allow the boot to have a very large walk-mode range of motion, similar to the Alien-style boots, and far better than the current telemark boots.

    This same spring also provides added flex to the cuff when locked in downhill mode. This is something telemark skiers should find appealing, as many currently ski downhill with their boots in walk mode, or have rigged up bungee-type systems to allow more flex.

    Mismatched flex between cuff and bellows is a frequent complaint about Scarpa's current telemark boots. In Scarpa's defense, it's a tricky thing to design for given different skiers' techniques and biomechanics. Having a spring provide the flex -- rather than relying on elastically-deforming plastic -- has several benefits:

    - There is less stress on plastic components (and thus less reliance on a specific strain). This should improve longevity and/or allow the use of lighter-weight materials that might not be as durable when flexed.

    - The spring could ostensibly be replaced when it wears out, or to provide a customized feel.

    - Relying on plastic to deform means there is the potential for loss of lateral stability. A spring compressing on an anchored, telescoping lever (with plastic not being asked to deform as much) should help lateral stability.

    There's not a drawing of the medial side of the boot, but it kinda looks like it has the standard buckle running from the medial pivot to the lateral cuff (sorry, tele.skier ). That said, the patent is mainly for the mode lever, so that part of the drawing likely means nothing.

    I hope they chose a super-cheesy name for this feature, like the "TELEscope"

    Will it make creaking sounds? Will we have to lube our tele boots?

    This lever appears to differ from the Phantom ones in that one spring holds the lever in place while also providing forward flex. I may be wrong, but it appears the Phantom ones have separate mechanisms for these functions. The Scarpa design should enable it to be sleeker/lighter. Also, the spring on the Scarpa ones stays fixed on the cuff, and the lever's pivot has some slick nubs/grooves incorporated that allow it to perform its various functions in conjunction with the spring.

    A tele boot like this also seems like it could have great snowboarding performance. The patent doesn't mention it, but could Scarpa be preparing -- intentionally or unintentionally -- for entry into the world of hardboot and/or splitboard snowboarding?
    Last edited by bobbytooslow; 29 June 2020, 04:28 PM.


    • #3
      to me it looks like the drawing is the concept on a maestrale2, not a telemark boot. That doesn't mean much. it is typical for companies to put the invention on a generic item, not some forthcoming item.

      but in principle it could mean that they can tune a stiffness without having to change the durometer or shape of the plastic. Don't think this is a game changing feature, but could definitely increase the "range" of an N boot line with new mix/match part options.

      i like TeleSpring better. or maybe TeleBoing which we can call TeleBong instead.

      btw, i already lube my boots, super lube smeared in the rubbing locations between cuff and scaffo. cuts friction a surprising amount.


      • #4
        Originally posted by jasonq View Post
        to me it looks like the drawing is the concept on a maestrale2, not a telemark boot. That doesn't mean much. it is typical for companies to put the invention on a generic item, not some forthcoming item.
        Yeah, the drawings in this patent are adapted from drawings in the patent that describes the current Maestrale mode lever. The difference being the location of the spring and, reading the text, that in the earlier patent the spring's only function is to hold the lever up or down (not to provide travel). The newer design is pretty slick, and would certainly make a lot of sense for use on telemark (and hard snowboard) boots.

        Having a shared upper with the Maestrale would jive with Kim Miller's comment that "If you're an AT and tele skier, you'll see a lot of similarities to your AT boots. It's gonna feel very stealth and compact, it's lighter, it's got more range of motion, it's got more modern mechanisms like ski/walk... If you covered up the bottom centimeter and the bellows you wouldn't know it's a telemark boot."

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        • #5
          Having started on my own boot modifications, I can tell you that one of the limiting factors to free cuff movement in walk mode is the old cuff lock mechanism, and I have issues to address modifying it. Seeing that scarpa realizes the old mechanism needs to be changed is encouraging.

          The elasticity of the cuff lock mechanism in ski mode is interesting, but my entire technique is based on driving the cuff with my shins. If I am resort skiing then cuff stiffness makes my boot a stiffer lever which I don't think is a bad thing inbounds. When I am touring, I give up that cuff stiffness (boot leverage), not because it wouldn't be an advantage on the downhill leg of the tour, but because it would be a burden on the uphill leg.

          I'm not sure what scarpa is getting at with the spring mechanism, but it's not something I would endorse or reject until I tried it. Maybe there's an "AHA!" moment where it changes the whole dynamic feeling for the better.... (or worse)

          I'd love to see the group of skiers advising scarpa on their design requirments. I'd like to see them ski too and have a look at their gear preferences... the gear you prefer says a lot about your technique.
          Last edited by tele.skier; 29 June 2020, 06:21 PM.
          the fall line is your friend.... resistance is futile


          • #6
            Question, for a tele boot do you really need a huge range of motion touring? Just curious what the benefits are and drawbacks? I have never toured in AT boots.


            • #7
              last night I was dreaming vividly about the spring mounted locking lever,... And I came to the solution while I was asleep. The spring isn't part of the lever mechanism. The spring just holds the lever in place against a cam depression when it's locked or unlocked. That cam shaped part, under pressure from the spring keeps the walk mode lever from swinging away from it's intended position... so it stays where you put it...
              the fall line is your friend.... resistance is futile


              • #8
                ROM makes a big difference. You can lengthen your stride into a much more efficient motion when climbing steep and breaking trail in deep snow. Even with my Frankenboots with a Rush cuff married to a TX Pro shell, I get a nice improvement but strong AT skiers with modern boots still pull away from me on long days.

                Regarding the spring, I guess I just don't put that much force on my boot because I can't imagine me creating a force that would even fatigue the cuff, much less break it. They definitely would not want my advice because I ski their boots unbuckled because I find even the TX Pro cuff too stiff.

                As I've stated before, I really like to flex my ankles and ride from the middle of the ski. Leaning on the cuff is painful where I've got nerve damage but even before then, I always skied T1s in walk mode. My Frankenboots, if anyone recalls, have a metal bar held in place by a wing head screw into a T-nut in the shell. I agree, tele.skier, that the Scarpa mode switch leaves much to be desired. But I also think the design of the boot limits ROM in tour mode with those tabs on the back of the shell and the forward lean angle designed into the cuff that renders the mode switch even more useless because the cuff/shell interface just doesn't pivot enough even with the switch removed.

                I've obtained something like 20.6 degrees total ROM from my ski mode, which is 17.5 degrees, about half way between the TX Pro ski modes of 14.2 and 19.4 degrees (my measurements). So my most backward position is only -3.1 degrees from vertical, while the TX Pro most backward position is +10.2 degrees. Shockingly poor for touring and my improvement feels a lot better but as I said, still has me working harder to skin at the pace AT skiers with modern boots can skin at with ease. At least I feel like I’m in the same ballpark even though I’m not very close to what AT boots have.

                Consequently, if Scarpa can get the ROM of a Maestrale into a tele boot, that will be a real game changer. I don’t understand the spring in the switch to provide a little movement. Seems overly complicated to my simple brain.


                • #9
                  Originally posted by tele.skier View Post
                  last night I was dreaming vividly about the spring mounted locking lever,... And I came to the solution while I was asleep. The spring isn't part of the lever mechanism. The spring just holds the lever in place against a cam depression when it's locked or unlocked. That cam shaped part, under pressure from the spring keeps the walk mode lever from swinging away from it's intended position... so it stays where you put it...
                  But the verbiage in the patent says to me that it allows some movement against the spring before the cuff starts to deform. That's the part that I don't get because fatiguing the cuff seems like it's not a problem for me.


                  • #10
                    If you look at the drawing, Fig 1 it shows a slot for the pivot point of the walk lever, so it does indeed have some travel in ski mode and some spring tension between the cuff and the locking mechanism, but it also has a hard limit on the travel in both directions too... Ya' got me what that is supposed to do... It's not something I foresaw as a needed improvement.
                    the fall line is your friend.... resistance is futile


                    • #11
                      Yup, the amount of spring travel is limited by the length of slot 21. Folks who like the sensation (or need it, in the case of splitboarders) could ostensibly swap out the mounting bracket (16) for one with a larger slot.

                      What's the point? To enable the use of stronger, lighter materials. It seems they've gone as far as they can go with Pebax; making a full-Pebax boot weigh less than say 1400g seems pretty difficult. Very few of the lighter AT boots use Pebax anymore, they're mostly a combination of Grilamid and carbon fiber. From my limited understanding, those materials don't flex/recover as well as Pebax -- not that AT boots need to flex/recover as much as tele boots -- so the answer is to use a stiffer material and get the flex other ways. If flex is fully regulated by the cuff and mode lever, it could also allow you to eliminate the tongue, which adds weight and, as this thread discusses, is an inhibitor to touring freedom.

                      (Once the tongue isn't part of the equation, and if the ankle rivet is aligned perfectly with the ankle joint axis -- yeah it's a bit different for dorsiflexion vs plantarflexion, whatever -- you could theoretically keep the cuff closure buckles/straps closed all the time. Kinda like a skate skiing boot. Having the option for that extra control could be nice for sidehilling and for breaking trail in deep snow. In rolling terrain, it'd be nice to switch modes with a quick flick of your ski pole. As mentioned elsewhere, one boot could meet the needs of both the XCD meadow-skipping crowd and the ultralight skimo-tele crowd.)

                      Anyway, look at the popular 1000-1200g AT boots (Scarpa F1, Alien RS, Fischer Travers, Sportiva Sytron, etc). They all have no tongue. To get a tele boot into that class of weight & ROM, while still flexing the way a tele boot needs to, it would seem that solutions have to go beyond just the bending of plastic. Or maybe I'm totally wrong, and the spring is just for the next Maestrales, and tele boots will continue to be technologically inferior.

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                      • #12
                        BBTS, I just can't wrap my head around a company that eliminated their only decent tele touring boot, deciding to make the ambitious boot design you propose. I've already expressed my very strong doubts that they are going make the boot that "I" want, or anything close to that boot. I would love to be wrong about that, but the last boot scenario with no tech fittings put into the Comp, the elimination of the Tx, and the worst boot of their 3 boot line up being their "go to" boot, has made me a pessimist.
                        the fall line is your friend.... resistance is futile


                        • #13
                          i think BTS is correct in that adding the spring means the plastic doesn't need to flex as much, and that could open up choices of plastics, and maybe thinner walls. But it would be the same on an AT boot as a Tele boot, since really the fundamental difference is the bellows, or rather tele boots must have bellows* while AT boots could have bellows. whether any advantage could be taken without the boot cracking, not sure.

                          I see this being much more applicable to full carbon AT boots that don't flex very well. again, not a game changer, but another tool to use.

                          *i do not believe this has been conclusive shown to be true. A complicated binding could possibly mimic the motion of having a bellows from the ball of the foot back. not saying it would work, just saying i have not seen any attempts at a bellow-less boot binding system and can see ways it might work.


                          • #14
                            Maybe Dostie or Madsen will break the silence this Winter and offer a sneak peak. I am sure there is some beta tele boots floating around Boulder and Salt Lake area.


                            • #15
                              I like this idea. I used to ski my T2's in walk mode to get the same result. The miniscule ROM and stiff cuff/tongue/liner acted like a spring before reaching the point of deforming the boot material.

                              I hope Scarpa implements this on a telemark boot because it would be an indication that the boot has more ROM and less touring resistance. To put it another way, the TXP wouldn't benefit from that spring because it wouldn't be much different from skiing in walk mode. And the F1 Race wouldn't benefit from the spring because the material is so soft that it already flexes a ton in ski mode.

                              So, if this is a sign of a stiff telemark boot with high ROM, low touring resistance, and tunable resistance in ski mode (via spring preload), I'm excited.