Lip snarl- for mask

I am looking to do some snarl mechanics in some commissioned mask work. I've tried some RnD already, but have still come up empty. 
Several years ago, I purchased one of those cheap werewolf masks with a snarl mechanism. I thought I  could replicate it with some improvements, but I have been proven wrong by both   physics and mechanics. 
Attached are my current designs. 

Could anyone help give me input? 
I'd like to design something that isn't patented, so everyone can use it. 
The  lines I've used  go from lower jaw, arching over the upper jaw, but under the resin nose form, to the opposite  upper lip. 
I am using fishing leads as my cables. 

The tension seems to  be too great. I'm making these so that they activate with the jaw mechanism. 

Comments

  • Chris EllerbyChris Ellerby Los Angeles Admin
    Hi Kierstin,

    Your design looks great! 

    If you are having issues with then tension you may want to switch from fishing line to metal cable inside a plastic housing.  For heavy-duty applications bicycle bake cables work good, but for this I would try RC aircraft push/pull cable linkages.  I usually use the ones with the yellow housing from Sullivan Products.  (you can search amazon/online for "Sullivan Products cable")

    /Chris
  • Thanks Chris! 

    I got those cables, and BOY what a difference! 
    Thank you so much! I finished doing a test rigging with the new cables, and they are much more reactive! The only issue is right now, the  length of the snarl, determines how wide the mouth opens. 
    So at maximum snarl, the mouth's maximum range isn't very wide. 

    I'm  guessing that if I want the widest mouth "roar" then the lip snarl will have to be activated via a hand cable control, instead of the jaw. 

    I tried attaching springs to the  ends of the anchors, so at maximum snarl, the jaw is still able to open wider, past the snarl point. The only issue, is the cable isn't easily pushed BACK into position unless I solder the anchor points between the tension spring, and the cable. I don't have the tools to do that, so I'm at a stand still with my research on that front. 

    My hope  is that once this all comes together, and I am successful, I can help make a tutorial for others wanting to do the same. 
    Snarl mechanisms seem to he a highly protected trade secret, and even patented. 
    I just want to see others be creative and improve on the idea. 

    Thank you so much for your help! 
    If you have any other pointers, I'm all ears, and thirsty to learn! 
    I hope you are doing alright! 
    -K
  • Chris EllerbyChris Ellerby Los Angeles Admin
    Glad you are having better luck with the new cables!

    The relationship of jaw movement to snarl movement is based on where you attach your cables to the jaw.  The closer to the pivot point you connect, the less movement you will get.  The further forward, the more the jaw will move, and the more the snarl will move.   There are 2 tradeoffs though.  The further forward you go, the less leverage you will get, so more force may be needed.  And if you are too far forward you risk the cables being seen if you can not disguise them.

    As to your challenges with getting the lip to return after the snarl, if gravity is not enough, springs or elastic can help.  They will just be a bit of extra force to overcome when the jaw moves the snarl.

    If you have photos of your setup that could help troubleshoot things.

    /Chris
  • Hey Chris! 

    Thank you so much for your reply! 
    I  made a video, because I feel like there was a tad much to be said, and I'd be sending you an enormous album and even more sketches to try and communicate when I'm struggling with. 
    Hopefully I did better with spoken words in the video. 

    Let me know if you have any suggestions and/or questions! 
    -K

    https://www.youtube.com/watch?v=y8CHMKXqU-0
  • Chris EllerbyChris Ellerby Los Angeles Admin
    Hi Kierstin,

    First off, those characters both look great!

    For the snarl cables, do you have them inside a plastic housing, or are you running the metal cable between the two points on its own?  You should be able to run the cable fairly long distances and not add too much resistance as long as it's in a housing and does not make any super tight turns.  The housing just needs to be anchored at each end so the cable can slide freely inside it.  Just like a brake cable on a bike.

    The other U shaped mechanism you mentioned is a common one, and a variation of that might be an option for you.  Rather than a full U each side could end just where the snarl attachment point would be, so it would not go all the way around the top gum line.  Then you would just need an identical mech on the other side to handle the other snarl point.  These mechs are great because they can be pretty durable, but the big challenge is having them move behind the skin without showing motion where it's not wanted.  

    One other thing that may help fine-tune the movement after you figure out the mechs would be to tack down the nose or the front lip (even using velcro, a snap, etc.  I try never to make attachments permanent if I can avoid it) to help isolate the movement to just the snarl point you are interested in.

    /Chris
  • Thank you so much, Chris! 

    Very good points, I will see what I can do. 
    And yes, they are "naked". I've tried it with the housing, but it makes them way too stiff, and they don't lay down right under the flesh.  When I add the housing, the whole muzzle floats up,  like a bad dentist's visit. Even more difficult is the housing doesn't take well  to hot glue which I use to tack it  into place in a temporary manner (isopropyl alcohol pops it right  off) for testing.
    The only way I can think to avoid that would be to have the wires cross inside of the underskull, but then the arch and tension becomes a whole new problem, somehow. 
    There's a math equation for this, I'm just not sure what it is. 

    So, I did a test this morning, having secured the wires in a cross arch, like I had originally planned, but I secured them in a manner, very similar to the way I did the wookie, further back. 
    SO FAR it seems to have worked. 
    The silicone  didn't hold to the cables, so they  slipped free before I got any video. 
    I'll try again today, with  the fabric hot glued to the loop of wire, and then silicone the fabric to the lip, as the fabric can soak in the silicone. 

    I'll keep you updated!
    -K

  • Chris EllerbyChris Ellerby Los Angeles Admin
    Glad you are making progress!

    I would recommend finding a way to use the housing if possible since it keeps the cable from binding or abrading on other surfaces and keeps friction down.  Running it on the inside might be a good idea, or you can carve channels for it.  I usually tack down the housing with a bit of epoxy putty once I know the positions and angles.

    The housing you have is just a plastic tube right?  That should not increase the profile of the wire too much unless it's the kind that has a coiled housing inside, as those can be a bit thicker.

    /Chris
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