Hip Winches

A project log for SHE BON

! a platform for sensing and indicating human arousal !

Sarah PetkusSarah Petkus 09/25/2018 at 22:231 Comment

My goal this past week was to create a belt of hip-mounted winches! 

Why, you ask? In short, my next peripheral for SHE BON require I scheme up a mechanism that is able to create thigh gap between my legs by pulling apart the meat of my buns. You can read more about this on my introductory post about the HOT SPOT.

For this cause, I decided to use a pulley/tendon system, which yanks at a long strip of kevlar rope adhered at a diagonal bias across the plane of my flesh just below my buns.

  1. To do this, I first had to calculate how strong my motors would need to be in order to supply enough torque for the job. 
  2. Second, I'd have to mount these said motors at the right angle on my fleshy body, however solidly enough so that they stay put relative to the pieces being tugged.

The later is as challenging as it sounds. I'm running into much the same issues as with my propellor pasties: the human body is a terrible anchor point for mechanical components... *sigh*


At some point earlier this summer, I knew I would need some torquey motors strong enough to lift the dense meat of my body against gravity. I also knew, I didn't want anything too terribly powerful, as I don't wish to have my butt literally ripped apart either.

Luckily, I had a friend who is somewhat of a mechanical engineer. NoodleFeet's shape daddy assumed the roll of "butt technician" for a night, and helped me rig up a test environment for the purpose of calculating how many ounce-inches of torque it would take to do the task I required.

I am currently producing a video that explains this process a bit more in depth; in short it has to do with springs, calipers, and weights. =P

Once all was said and done, I learned some fun numbers I never thought I'd know. It takes 9.5 pounds of raw force to pull my bun up and apart. This comes out to 150 ounce inches of torque. YAY


I decided early on to fashion some sort of "belt" that leverages the relative static position of my pelvis bone...since alignment and solid mounting are key. 

I cross-crossed two thin strips of sheet ABS plastic across the front of my tummy, so that the strips would ride just above and below where my hips protrude. Once tightened, the bone is sandwiched tightly, and the belt can't move up or down very much! 


The next step was to create something in CAD that would bridge the winch to the belt, like a mounting bracket. 

Since the belt leverages the relative static position of my hips, the winches would need to mount somewhere along this area. 

It made sense to me that the frame-bracket aught to cup the protruding hip bone, with the mounting points somewhere opposite from the point of pull.

If I take this one step further and consider aesthetics regarding the full ensemble, then it also made equal sense that this hip mounted motor be housed in some sort of wing or fin... star and shabby, much a like a fundamental or mech:

The next step is to work out how the cable or tendon will adhere to my thighs. Originally I was thinking of using some sort of liquid bandage or medical adhesive to do the trick... but seeing as how the quick and easy (also affordable) gorilla tape also proved to be effective, I will use it in the beginning- for now.

I will likely rig up a test environment for the whole system sometime this week. Hopefully I don't tear anything, or burn out the motors =P

Once it's in a somewhat working state, you know a video update will follow explaining the outcome.

until then, cheers and happy October 1st!!! Go get those pumpkin doughnuts. 



Jan wrote 10/02/2018 at 13:37 point

The serious amount of serious (yes, it's double serious) work you put into that project is overwhelming. One could say you're really feeling it *slow clap* :)
The combination of µC-stuff, engineering and taking butt-lift-force-measurements is unique.
I'm really curious where this is heading in the end!

  Are you sure? yes | no