Hanging A Realdoll Vertically
Moderator: TJ_Foxx
Hanging A Realdoll Vertically
George66 has solved the problem by modifying Emma's head. I am too chicken to try this on Claire, so I've had a go at designing a Lifting Bracket to achieve the same thing.
It is simply a vertical rod, rigidly fixd to the neck bolt, with a 4 inch bar at the top, to put the lifting rope over the centre of her head. I've taken a few pictures of its construction, which can be seen by clicking on this thumbnail:-
The rod material is silver steel (about 50Ton/sq.in). It needs to be high strength because there's a high bending moment from the overhang of the doll's weight. It may not be clear from the pictures, but I've had to put a steel tube around the vertical 3/8in rod. I had to do this, because the rod wasn't strong or stiff enough. A better design would be to do away witht the tube and use a 7/16in diameter rod. The rod has a 5/8in UNF thread each end, of 1in length to attach the top and bottom components. All the remaining components are Mild Steel. I obtained the materials from a model engineering supplier on the internet.
I made the bottom nuts myself, as I'm a tightwad but I could have purchased ones instead. The main thing is to really tighten this connection onto the neck bolt.
A 4in offset seems to work. I would not feel comfortable with any more, as this may put too much bending into the neck bolt, which, although high strength, is only a 3/8in UNC thread.
Hope this is of interest. the end result can be seen in Clair's album:-
Great idea!
You put quite a moment on the neckbolt.
But it really corrects for the distance the neckbolt is from the "centre" of gravity of the doll.
She really stands straight while hanging free.
Its a neat solution, and looks better than a bolt in the centre of the top of the head.
Mytime & Helen
One dream, one mission...
Interesting solution, thanks for showing us, I shall make one up myself.
You mentioned George 66`s solution to the problem, did I miss the posting on how he achevided his idea??, would you be able to link to the post as I would be very interested to see how he acheived his conversion.
cheers R.
Edit........
Belay that request for info, found it under G66 profile, I shall look into that method as well, if I remember correctly thats the way superbabes are suspended.
With a mass of 85lbs acting over a 4in arm, the moment is 340in.lbf
Using the bending stress formula My/I the bending stress is 58Ton/sq.in (896MPa).
I'm assuming the bolt is a high strength steel (something like a 12.8 Standard bolt type) which has a yield strength of 65Ton/sq.in (1000Mpa). This means the bolt has a small margin before it bends at a 4in arm.
Cyclops, the thing sticking out of the top isn't a bungee as Claire is bouncy enough already
It's actually a piece of nylon cord to which I hook a block and tackle when lifting Claire. The cord just takes the block out of shot when I photograph her. The cordage and blocks are the same type as those used by George66, purchased from a yacht chandlers. They are designed for sail boat rigging being light weight and strong. The cord is only 1/4in diameter.
midnight, I knew my job would come in useful one day
Regards,
Dave.
I come an end, but here hence I = 0.000387in^4. you're calculating a value I can't place.
I have had physics, but I'am not a person that knows all ins and outs of calculating on metal pieces. (I'am not a Jerry).
Maybe that's the reason why I don't get that constant.
Mytime & Helen
One dream, one mission...
Mytime, I cut out some of my calculation just in case it bored people. But to explain, "I" we call the "second moment of area" and is used in bending calculations. For a circular section, the formula is:-
I = (pi x diameter^4)/64 where pi = 3.14159
so I of the neck bolt = (3.14159x.298^4) /64 = 0.000387in^4
For a rectangular section I = width x depth^3 / 12
so I of bracket top bar = .75 x .75^3 /12 = .0263in^4
The bigger the value of I the smaller the bending stress and the less likely the section will break.
In the formula I mentioned: Stress = My/I
M is the bending moment, y is half the diameter (or half the section height for a rectangular section) and I is the second moment of area.
OK perhaps everyone's fallen asleep so I'll stop there