Agreeable Sheep. Mk iii Prototype

Mon, 2 Jun 2014

I’m in the process of updating the website – it’s going to take a while, there’s a lot to do so I’m doing it in small steps. First things first, I want a ‘start here’ free-to-download model. My plan is to use the Agreeable Sheep, a timeless classic, I’m sure you’ll agree. I set about making up a model for photography only to find out that I’d made a few improvements in my model making techniques since the last version was made. Time to make the mk iii Agreeable Sheep!

First things first, round axles. And while I’m at it I decided to change the cam profile so that the head nods more than once for each turn to the handle. My first attempt was with this saw-tooth cam profile.

I glued a coin to the bottom of the cam follower for weight then added a triangle section tube below the coin to run on the cam. Although it worked smoothly there are two problems. Firstly the thickness of the coin could vary for different users introducing an uncontrolled variable. Secondly, the saw tooth profile only works in one direction. Try to turn the handle backwards and it locks against the cam follower.

I made a few changes and put together another model. In this version the coin is on the top of the cam follower. This eliminates the thickness issue. The cam profile is now a rounded equilateral triangle. It works smoothly in both directions.

And here it is put together. I’ll make a couple of minor changes and it will be ready for release. Agreeable Sheep mk iii. Yes!