Saturday, 10 December 2016

Automaton Evolution

As I've improved the various bits of the automaton and built them up on the prototype I realised that I didn't want to keep remaking parts. Unfortunately the right arm is fixed to a cranked shaft which goes through the body to the operating lever. The parts are too small to be easily threaded or fixed together in some way that can be taken apart, I'd been mulling over this for some time when the solution struck me. I have sawed through the shoulder pivot point then screwed it back together and re-drilled the bearing hole, this way it can be taken apart much like a main bearing on the crankshaft of a car engine. I've also made a mount for the bow which allows me to adjust it, the previous bow was just stuck in place and had no adjustment.
The new bow is made of the Cherry I cut a few days ago and seems to bend nicely with much better tiller, seasoning isn't a problem with such a thin sliver of wood.
The drawing hand has been cut from tin plate and seems to line up and catch the string quite well. there is a lot of trial and error and adjustment, slowly improving each part. The biggest change is the canting of the bow across the body in a much more realistic manner which also gives it a bit more of a 3D look.
Note, the full draw pic looks a bit off due to the canting of the bow and the camera angle. (It makes the bottom limb look too short).For each problem I solve another appears, the canted bow looks better and allows the fingers to hook onto the string better, but the lower limb goes behind the archer when the bow arm is down and clashes with the control rods which will operate the arms. For now I'm getting the geometry of each arm individually and working out clearances, I'll then have to implement both arms at once. Lots of fiddling and fettling I'll probably have to bend the operating rods all over the place to get it right.

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