Quick update

Thought I'd post a few photos related to my current attempts.

I was going though my Japan trip photos and came across a display at the Karakuri Museum in Nagoya. These show the process of designing and constructing an archer karakuri as done by the current master of karakuri, Shobei Tamaya IX,  The only disappointing thing to note is that I failed to get a clear photo of the center of the display that showed the cams in detail! Oh Man!

 And finally here is a shot of a classic example of Karakuri at it's height. This wonderful piece is in the Toyota Museum of Industry collection in Nagoya.

Cams and Grommets...

Hi again!
I had a three or four hour stint in the little corner basement workshop this week. Nothing too dramatic was achieved, but I did manage to start to add the grommets for the strings to follow - you can see them here... You can see in this photo the 'stops' built into the arms so that when the bow arm is in tension, it should straighten out completely.
Also I added the third smaller gear to the 'drive' of the doll. This has slowed the potential action of the doll when it is cranked, just in case any quick motion might have damaged the mechanisms. This has allowed me to move the handle slightly up. Might save some knuckle skin in the long run.


Tonight I've started to break down the cycle of the movements and made a primitive drawing of the possible cam shapes. I have five cams designed into the base, four are now accounted for. One for the up and down motion of the shoulders, moving both the arms up. The next one straightens the bow arm, while the other arm cam bends the forearm of the string arm forward. The fourth cam should pull the upper part of the string arm in the opposite direction as the bow is drawn.

I'm thinking now, as I type this, that the fifth cam could be used to activate the trigger hand to release the bow string - but that might be a tougher done than said.
Here's my very rough drawing of the cam designs based on breaking the time down into 360 degrees. As I've said before, this Kyudo doll won't do every movement precisely, just mimic most of them. I found a video online of a gal putting on quite a performance, and basically decided to time the motions so that the up and down movements of the arms would be the point where the doll would 'cycle' to it's beginning stance. Unfortunately my skills are not up to snuff so much to include the relaxed pose of the archer at the end of the shot. You can see the video that inspired me here.
I'll have to wait another week before I can string this doll up -- sigh. 
Before I go, one more online treat is an old black and white film of Kyudo archers in full armor practicing their combat skills. This is quite amazing, and I think that armor design has given me a few ideas on how to decorate my archer.


Here's something to make your mind buzz for now...

The 'Archer' takes shape...

Here's the latest state (sort-of) of the Kyudo archer karakuri:

There's so much more to do with this project I don't know where to start...

It might look a bit elegant for now, but the most important parts, the strings and levers, are still to be figured out.

This is not the most recent state, but it's close. What I have done since this photo was taken was re-design the bow arm, re-design the chest area, and generally clean up the rough look of this doll. I've narrowed the waist a bit so that his shoulders appear wider, and the bow arm is designed now with 'stops' built into it. Basically the limits of motion have been re-designed into the arm. This will help to stop the arms from flopping in the wrong direction once under tension.

Next on the to-do list is: 

-add a third smaller gear to the geartrain and attach the crank/handle to this new gear. (This will slow the motion down by a factor of four, at least I hope so...

-I have some hair to attach - which I will do soon because it's always nice to see your figure 'come alive'. This tends to help focus on the detailing I find...

-space out the cam wheels with plastic bearings, and then take all but one out, and then string up my first range of motion The first basic 'range of motion' will be the up and down movement of the shoulders/arms. Here's an image from the web showing the motion flow of a Kyudo archer-

Essentially I want to emulate the steps from about the third figure in to the seventh figure, and cycle back to the third. I won't be able to raise the arms up as high as this figure shows, but it should be close.

- next I need to figure out how to string the doll's arms to get the leverage I will need to have realistic motion. This will be the most difficult part. I suspect I'll have to re-design a number of cams to make this work.

I have an idea how to go about designing the various motions, and I'll share that with you next time...

'Till the next day in the shop I'll be reviewing the finished idea over and over in my head. I does help!